diff --git a/src/SourceBuild/content/Directory.Build.props b/src/SourceBuild/content/Directory.Build.props
index ddfc7cced..89e25c6ad 100644
--- a/src/SourceBuild/content/Directory.Build.props
+++ b/src/SourceBuild/content/Directory.Build.props
@@ -4,11 +4,12 @@
     <ImportNetSdkFromRepoToolset>false</ImportNetSdkFromRepoToolset>
     <_SuppressSdkImports>true</_SuppressSdkImports>
     <Configuration Condition="$(Configuration) == ''">Release</Configuration>
-    <NetCurrent>net9.0</NetCurrent>
   </PropertyGroup>
 
   <Import Condition="'$(SkipArcadeSdkImport)' != 'true'" Project="Sdk.props" Sdk="Microsoft.DotNet.Arcade.Sdk" />
   <PropertyGroup>
+    <!-- TODO: Remove NetCurrent override: https://github.com/dotnet/source-build/issues/3743 -->
+    <NetCurrent>net9.0</NetCurrent>
     <!-- Fake, for SDK. -->
     <TargetFramework>netstandard2.0</TargetFramework>
     <!-- We have no projects targeting multiple frameworks, so don't include in output path. -->
diff --git a/src/SourceBuild/content/eng/Versions.props b/src/SourceBuild/content/eng/Versions.props
index bc3e36745..092f38583 100644
--- a/src/SourceBuild/content/eng/Versions.props
+++ b/src/SourceBuild/content/eng/Versions.props
@@ -28,8 +28,8 @@
       of a .NET major or minor release, prebuilts may be needed. When the release is mature, prebuilts
       are not necessary, and this property is removed from the file.
     -->
-    <PrivateSourceBuiltSdkVersion>8.0.100-rc.2.23502.1</PrivateSourceBuiltSdkVersion>
-    <PrivateSourceBuiltArtifactsVersion>8.0.100-rc.2.23502.1</PrivateSourceBuiltArtifactsVersion>
-    <PrivateSourceBuiltPrebuiltsVersion>0.1.0-9.0.100-4</PrivateSourceBuiltPrebuiltsVersion>
+    <PrivateSourceBuiltSdkVersion>9.0.100-alpha.1.23557.1</PrivateSourceBuiltSdkVersion>
+    <PrivateSourceBuiltArtifactsVersion>9.0.100-alpha.1.23557.1</PrivateSourceBuiltArtifactsVersion>
+    <PrivateSourceBuiltPrebuiltsVersion>0.1.0-9.0.100-6</PrivateSourceBuiltPrebuiltsVersion>
   </PropertyGroup>
 </Project>
diff --git a/src/SourceBuild/content/repo-projects/Directory.Build.props b/src/SourceBuild/content/repo-projects/Directory.Build.props
index b946439d4..fc963c600 100644
--- a/src/SourceBuild/content/repo-projects/Directory.Build.props
+++ b/src/SourceBuild/content/repo-projects/Directory.Build.props
@@ -77,7 +77,10 @@
     <EnvironmentVariables Include="_InitializeDotNetCli=$(DotNetCliToolDir)" />
     <EnvironmentVariables Include="_DotNetInstallDir=$(DotNetCliToolDir)" />
     <EnvironmentVariables Include="_InitializeToolset=$(SourceBuiltSdksDir)Microsoft.DotNet.Arcade.Sdk/tools/Build.proj" Condition="'$(UseBootstrapArcade)' != 'true'" />
-    <EnvironmentVariables Include="_OverrideArcadeInitializeBuildToolFramework=$(NetCurrent)" />
+
+    <!-- TODO: Revert net8.0 bootstrapping hack: https://github.com/dotnet/source-build/issues/3743-->
+    <EnvironmentVariables Include="_OverrideArcadeInitializeBuildToolFramework=$(NetCurrent)" Condition="'$(UseBootstrapArcade)' != 'true'"  />
+    <EnvironmentVariables Include="_OverrideArcadeInitializeBuildToolFramework=net8.0" Condition="'$(UseBootstrapArcade)' == 'true'"  />
 
     <EnvironmentVariables Include="DotNetUseShippingVersions=true" />
 
diff --git a/src/SourceBuild/content/repo-projects/Directory.Build.targets b/src/SourceBuild/content/repo-projects/Directory.Build.targets
index baaa8cf59..07aefc4d8 100644
--- a/src/SourceBuild/content/repo-projects/Directory.Build.targets
+++ b/src/SourceBuild/content/repo-projects/Directory.Build.targets
@@ -26,6 +26,20 @@
     <MSBuild Projects="@(_DependentProject)" Targets="Build" BuildInParallel="$(BuildInParallel)" StopOnFirstFailure="true" />
   </Target>
 
+  <!-- TODO: Remove this target: https://github.com/dotnet/source-build/issues/3743 -->
+  <Target Name="UpdateBuildToolFramework"
+          BeforeTargets="Build"
+          Condition="'$(EngCommonToolsShFile)' != ''"
+          Inputs="$(MSBuildProjectFullPath)"
+          Outputs="$(RepoCompletedSemaphorePath)UpdateBuildToolFramework.complete" >
+
+    <ReplaceTextInFile InputFile="$(EngCommonToolsShFile)"
+                       OldText="_InitializeBuildToolFramework=&quot;net8.0&quot;"
+                       NewText="_InitializeBuildToolFramework=&quot;net9.0&quot;" />
+
+    <WriteLinesToFile File="$(RepoCompletedSemaphorePath)UpdateBuildToolFramework.complete" Overwrite="true" />
+  </Target>
+
   <Target Name="UpdateNuGetConfig"
           BeforeTargets="Build"
           Condition="'$(NuGetConfigFile)' != '' OR '@(NuGetConfigFiles)' != ''"
diff --git a/src/SourceBuild/patches/arcade/0001-Use-net9.0-for-task-assembly-paths.patch b/src/SourceBuild/patches/arcade/0001-Use-net9.0-for-task-assembly-paths.patch
new file mode 100644
index 000000000..71bac9212
--- /dev/null
+++ b/src/SourceBuild/patches/arcade/0001-Use-net9.0-for-task-assembly-paths.patch
@@ -0,0 +1,232 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Matt Thalman <mthalman@microsoft.com>
+Date: Thu, 16 Nov 2023 14:42:59 -0600
+Subject: [PATCH] Use net9.0 for task assembly paths
+
+Backport: https://github.com/dotnet/source-build/issues/3743
+---
+ .../tools/BuildReleasePackages.targets                          | 2 +-
+ src/Microsoft.DotNet.Arcade.Sdk/tools/BuildTasks.props          | 2 +-
+ .../build/Microsoft.DotNet.Build.Tasks.Installers.props         | 2 +-
+ .../src/build/Packaging.common.targets                          | 2 +-
+ .../build/Microsoft.DotNet.Build.Tasks.TargetFramework.props    | 2 +-
+ .../src/build/Microsoft.DotNet.Build.Tasks.Workloads.props      | 2 +-
+ .../build/Microsoft.DotNet.Deployment.Tasks.Links.props         | 2 +-
+ .../build/Microsoft.DotNet.GenFacades.targets                   | 2 +-
+ .../Sdk/tools/Microsoft.DotNet.Helix.Sdk.props                  | 2 +-
+ .../build/Microsoft.DotNet.PackageTesting.props                 | 2 +-
+ src/Microsoft.DotNet.SharedFramework.Sdk/sdk/Sdk.props          | 2 +-
+ .../build/Microsoft.DotNet.SignTool.props                       | 2 +-
+ .../tasks/build/Microsoft.DotNet.SourceBuild.Tasks.props        | 2 +-
+ .../build/Microsoft.DotNet.SwaggerGenerator.MSBuild.props       | 2 +-
+ .../src/build/Microsoft.DotNet.XUnitConsoleRunner.props         | 2 +-
+ .../build/Microsoft.DotNet.XliffTasks.targets                   | 2 +-
+ 16 files changed, 16 insertions(+), 16 deletions(-)
+
+diff --git a/src/Microsoft.DotNet.Arcade.Sdk/tools/BuildReleasePackages.targets b/src/Microsoft.DotNet.Arcade.Sdk/tools/BuildReleasePackages.targets
+index af86865d..751a79c4 100644
+--- a/src/Microsoft.DotNet.Arcade.Sdk/tools/BuildReleasePackages.targets
++++ b/src/Microsoft.DotNet.Arcade.Sdk/tools/BuildReleasePackages.targets
+@@ -2,7 +2,7 @@
+ <Project>
+   <PropertyGroup>
+     <_NuGetRepackAssembly Condition="'$(MSBuildRuntimeType)' != 'Core'">$(NuGetPackageRoot)microsoft.dotnet.nugetrepack.tasks\$(MicrosoftDotnetNuGetRepackTasksVersion)\tools\net472\Microsoft.DotNet.NuGetRepack.Tasks.dll</_NuGetRepackAssembly>
+-    <_NuGetRepackAssembly Condition="'$(MSBuildRuntimeType)' == 'Core'">$(NuGetPackageRoot)microsoft.dotnet.nugetrepack.tasks\$(MicrosoftDotnetNuGetRepackTasksVersion)\tools\net8.0\Microsoft.DotNet.NuGetRepack.Tasks.dll</_NuGetRepackAssembly>
++    <_NuGetRepackAssembly Condition="'$(MSBuildRuntimeType)' == 'Core'">$(NuGetPackageRoot)microsoft.dotnet.nugetrepack.tasks\$(MicrosoftDotnetNuGetRepackTasksVersion)\tools\net9.0\Microsoft.DotNet.NuGetRepack.Tasks.dll</_NuGetRepackAssembly>
+   </PropertyGroup>
+ 
+   <UsingTask TaskName="Microsoft.DotNet.Tools.UpdatePackageVersionTask" AssemblyFile="$(_NuGetRepackAssembly)" />
+diff --git a/src/Microsoft.DotNet.Arcade.Sdk/tools/BuildTasks.props b/src/Microsoft.DotNet.Arcade.Sdk/tools/BuildTasks.props
+index 39214fef..74755a09 100644
+--- a/src/Microsoft.DotNet.Arcade.Sdk/tools/BuildTasks.props
++++ b/src/Microsoft.DotNet.Arcade.Sdk/tools/BuildTasks.props
+@@ -2,6 +2,6 @@
+ <Project>
+   <PropertyGroup>
+     <ArcadeSdkBuildTasksAssembly Condition="'$(MSBuildRuntimeType)' != 'Core'">$(MSBuildThisFileDirectory)net472\Microsoft.DotNet.Arcade.Sdk.dll</ArcadeSdkBuildTasksAssembly>
+-    <ArcadeSdkBuildTasksAssembly Condition="'$(MSBuildRuntimeType)' == 'Core'">$(MSBuildThisFileDirectory)net8.0\Microsoft.DotNet.Arcade.Sdk.dll</ArcadeSdkBuildTasksAssembly>
++    <ArcadeSdkBuildTasksAssembly Condition="'$(MSBuildRuntimeType)' == 'Core'">$(MSBuildThisFileDirectory)net9.0\Microsoft.DotNet.Arcade.Sdk.dll</ArcadeSdkBuildTasksAssembly>
+   </PropertyGroup>
+ </Project>
+diff --git a/src/Microsoft.DotNet.Build.Tasks.Installers/build/Microsoft.DotNet.Build.Tasks.Installers.props b/src/Microsoft.DotNet.Build.Tasks.Installers/build/Microsoft.DotNet.Build.Tasks.Installers.props
+index a7910488..6a8895b5 100644
+--- a/src/Microsoft.DotNet.Build.Tasks.Installers/build/Microsoft.DotNet.Build.Tasks.Installers.props
++++ b/src/Microsoft.DotNet.Build.Tasks.Installers/build/Microsoft.DotNet.Build.Tasks.Installers.props
+@@ -2,7 +2,7 @@
+ <Project>
+ 
+   <PropertyGroup>
+-    <MicrosoftDotNetBuildTasksInstallersTaskAssembly Condition="'$(MSBuildRuntimeType)' == 'Core'">$(MSBuildThisFileDirectory)..\tools\net8.0\Microsoft.DotNet.Build.Tasks.Installers.dll</MicrosoftDotNetBuildTasksInstallersTaskAssembly>
++    <MicrosoftDotNetBuildTasksInstallersTaskAssembly Condition="'$(MSBuildRuntimeType)' == 'Core'">$(MSBuildThisFileDirectory)..\tools\net9.0\Microsoft.DotNet.Build.Tasks.Installers.dll</MicrosoftDotNetBuildTasksInstallersTaskAssembly>
+     <MicrosoftDotNetBuildTasksInstallersTaskAssembly Condition="'$(MSBuildRuntimeType)' != 'Core'">$(MSBuildThisFileDirectory)..\tools\net472\Microsoft.DotNet.Build.Tasks.Installers.dll</MicrosoftDotNetBuildTasksInstallersTaskAssembly>
+     <MicrosoftDotNetBuildTasksInstallersMSBuildDir Condition="'$(MicrosoftDotNetBuildTasksInstallersMSBuildDir)' == ''">$(MSBuildThisFileDirectory)</MicrosoftDotNetBuildTasksInstallersMSBuildDir>
+   </PropertyGroup>
+diff --git a/src/Microsoft.DotNet.Build.Tasks.Packaging/src/build/Packaging.common.targets b/src/Microsoft.DotNet.Build.Tasks.Packaging/src/build/Packaging.common.targets
+index 99b1d490..4ae4de45 100644
+--- a/src/Microsoft.DotNet.Build.Tasks.Packaging/src/build/Packaging.common.targets
++++ b/src/Microsoft.DotNet.Build.Tasks.Packaging/src/build/Packaging.common.targets
+@@ -4,7 +4,7 @@
+   </PropertyGroup>
+ 
+   <PropertyGroup>
+-    <PackagingTaskDir Condition="'$(PackagingTaskDir)' == '' AND '$(MSBuildRuntimeType)' == 'core'">$(MSBuildThisFileDirectory)../tools/net8.0/</PackagingTaskDir>
++    <PackagingTaskDir Condition="'$(PackagingTaskDir)' == '' AND '$(MSBuildRuntimeType)' == 'core'">$(MSBuildThisFileDirectory)../tools/net9.0/</PackagingTaskDir>
+     <PackagingTaskDir Condition="'$(PackagingTaskDir)' == '' AND '$(MSBuildRuntimeType)' != 'core'">$(MSBuildThisFileDirectory)../tools/net472/</PackagingTaskDir>
+     <RuntimeIdGraphDefinitionFile Condition="'$(RuntimeIdGraphDefinitionFile)' == ''">$(MSBuildThisFileDirectory)runtime.json</RuntimeIdGraphDefinitionFile>
+ 
+diff --git a/src/Microsoft.DotNet.Build.Tasks.TargetFramework/src/build/Microsoft.DotNet.Build.Tasks.TargetFramework.props b/src/Microsoft.DotNet.Build.Tasks.TargetFramework/src/build/Microsoft.DotNet.Build.Tasks.TargetFramework.props
+index 9712b0ad..801ec5cd 100644
+--- a/src/Microsoft.DotNet.Build.Tasks.TargetFramework/src/build/Microsoft.DotNet.Build.Tasks.TargetFramework.props
++++ b/src/Microsoft.DotNet.Build.Tasks.TargetFramework/src/build/Microsoft.DotNet.Build.Tasks.TargetFramework.props
+@@ -1,7 +1,7 @@
+ <!-- Licensed to the .NET Foundation under one or more agreements. The .NET Foundation licenses this file to you under the MIT license. -->
+ <Project>
+   <PropertyGroup>
+-    <DotNetBuildTasksTargetFrameworkAssembly Condition="'$(MSBuildRuntimeType)' == 'core'">..\tools\net8.0\Microsoft.DotNet.Build.Tasks.TargetFramework.dll</DotNetBuildTasksTargetFrameworkAssembly>
++    <DotNetBuildTasksTargetFrameworkAssembly Condition="'$(MSBuildRuntimeType)' == 'core'">..\tools\net9.0\Microsoft.DotNet.Build.Tasks.TargetFramework.dll</DotNetBuildTasksTargetFrameworkAssembly>
+     <DotNetBuildTasksTargetFrameworkAssembly Condition="'$(MSBuildRuntimeType)' != 'core'">..\tools\net472\Microsoft.DotNet.Build.Tasks.TargetFramework.dll</DotNetBuildTasksTargetFrameworkAssembly>
+   </PropertyGroup>
+ </Project>
+diff --git a/src/Microsoft.DotNet.Build.Tasks.Workloads/src/build/Microsoft.DotNet.Build.Tasks.Workloads.props b/src/Microsoft.DotNet.Build.Tasks.Workloads/src/build/Microsoft.DotNet.Build.Tasks.Workloads.props
+index b7e95130..900fdb47 100644
+--- a/src/Microsoft.DotNet.Build.Tasks.Workloads/src/build/Microsoft.DotNet.Build.Tasks.Workloads.props
++++ b/src/Microsoft.DotNet.Build.Tasks.Workloads/src/build/Microsoft.DotNet.Build.Tasks.Workloads.props
+@@ -2,7 +2,7 @@
+ <Project>
+ 
+   <PropertyGroup>
+-    <MicrosoftDotNetBuildTasksWorkloadsAssembly Condition="'$(MSBuildRuntimeType)' == 'Core'">$(MSBuildThisFileDirectory)..\tools\net8.0\Microsoft.DotNet.Build.Tasks.Workloads.dll</MicrosoftDotNetBuildTasksWorkloadsAssembly>
++    <MicrosoftDotNetBuildTasksWorkloadsAssembly Condition="'$(MSBuildRuntimeType)' == 'Core'">$(MSBuildThisFileDirectory)..\tools\net9.0\Microsoft.DotNet.Build.Tasks.Workloads.dll</MicrosoftDotNetBuildTasksWorkloadsAssembly>
+     <MicrosoftDotNetBuildTasksWorkloadsAssembly Condition="'$(MSBuildRuntimeType)' != 'Core'">$(MSBuildThisFileDirectory)..\tools\net472\Microsoft.DotNet.Build.Tasks.Workloads.dll</MicrosoftDotNetBuildTasksWorkloadsAssembly>
+   </PropertyGroup>
+ 
+diff --git a/src/Microsoft.DotNet.Deployment.Tasks.Links/build/Microsoft.DotNet.Deployment.Tasks.Links.props b/src/Microsoft.DotNet.Deployment.Tasks.Links/build/Microsoft.DotNet.Deployment.Tasks.Links.props
+index 3ff65b8c..dcc23986 100644
+--- a/src/Microsoft.DotNet.Deployment.Tasks.Links/build/Microsoft.DotNet.Deployment.Tasks.Links.props
++++ b/src/Microsoft.DotNet.Deployment.Tasks.Links/build/Microsoft.DotNet.Deployment.Tasks.Links.props
+@@ -2,7 +2,7 @@
+ <Project>
+ 
+   <PropertyGroup>
+-    <MicrosoftDotNetDeploymentTasksLinksTaskAssembly Condition=" '$(MSBuildRuntimeType)' == 'Core' ">$(MSBuildThisFileDirectory)net8.0\Microsoft.DotNet.Deployment.Tasks.Links.dll</MicrosoftDotNetDeploymentTasksLinksTaskAssembly>
++    <MicrosoftDotNetDeploymentTasksLinksTaskAssembly Condition=" '$(MSBuildRuntimeType)' == 'Core' ">$(MSBuildThisFileDirectory)net9.0\Microsoft.DotNet.Deployment.Tasks.Links.dll</MicrosoftDotNetDeploymentTasksLinksTaskAssembly>
+     <MicrosoftDotNetDeploymentTasksLinksTaskAssembly Condition=" '$(MSBuildRuntimeType)' != 'Core' ">$(MSBuildThisFileDirectory)net472\Microsoft.DotNet.Deployment.Tasks.Links.dll</MicrosoftDotNetDeploymentTasksLinksTaskAssembly>
+   </PropertyGroup>
+ 
+diff --git a/src/Microsoft.DotNet.GenFacades/build/Microsoft.DotNet.GenFacades.targets b/src/Microsoft.DotNet.GenFacades/build/Microsoft.DotNet.GenFacades.targets
+index 65045a3a..98f22ef3 100644
+--- a/src/Microsoft.DotNet.GenFacades/build/Microsoft.DotNet.GenFacades.targets
++++ b/src/Microsoft.DotNet.GenFacades/build/Microsoft.DotNet.GenFacades.targets
+@@ -2,7 +2,7 @@
+ <Project>
+ 
+   <PropertyGroup>
+-    <GenFacadesTargetAssemblyPath Condition="'$(MSBuildRuntimeType)' == 'Core'">$(MSBuildThisFileDirectory)..\tools\net8.0\Microsoft.DotNet.GenFacades.dll</GenFacadesTargetAssemblyPath>
++    <GenFacadesTargetAssemblyPath Condition="'$(MSBuildRuntimeType)' == 'Core'">$(MSBuildThisFileDirectory)..\tools\net9.0\Microsoft.DotNet.GenFacades.dll</GenFacadesTargetAssemblyPath>
+     <GenFacadesTargetAssemblyPath Condition="'$(MSBuildRuntimeType)' != 'Core'">$(MSBuildThisFileDirectory)..\tools\net472\Microsoft.DotNet.GenFacades.dll</GenFacadesTargetAssemblyPath>
+   </PropertyGroup>
+ 
+diff --git a/src/Microsoft.DotNet.Helix/Sdk/tools/Microsoft.DotNet.Helix.Sdk.props b/src/Microsoft.DotNet.Helix/Sdk/tools/Microsoft.DotNet.Helix.Sdk.props
+index 1c51c182..ec91afae 100644
+--- a/src/Microsoft.DotNet.Helix/Sdk/tools/Microsoft.DotNet.Helix.Sdk.props
++++ b/src/Microsoft.DotNet.Helix/Sdk/tools/Microsoft.DotNet.Helix.Sdk.props
+@@ -4,7 +4,7 @@
+   <Import Project="$(MSBuildToolsPath)\Microsoft.NETCoreSdk.BundledVersions.props" Condition="Exists('$(MSBuildToolsPath)\Microsoft.NETCoreSdk.BundledVersions.props')" />
+ 
+   <PropertyGroup Condition="'$(MicrosoftDotNetHelixSdkTasksAssembly)' == ''">
+-    <MicrosoftDotNetHelixSdkTasksAssembly Condition="'$(MSBuildRuntimeType)' == 'Core'">$(MSBuildThisFileDirectory)net8.0/Microsoft.DotNet.Helix.Sdk.dll</MicrosoftDotNetHelixSdkTasksAssembly>
++    <MicrosoftDotNetHelixSdkTasksAssembly Condition="'$(MSBuildRuntimeType)' == 'Core'">$(MSBuildThisFileDirectory)net9.0/Microsoft.DotNet.Helix.Sdk.dll</MicrosoftDotNetHelixSdkTasksAssembly>
+     <MicrosoftDotNetHelixSdkTasksAssembly Condition="'$(MSBuildRuntimeType)' != 'Core'">$(MSBuildThisFileDirectory)net472/Microsoft.DotNet.Helix.Sdk.dll</MicrosoftDotNetHelixSdkTasksAssembly>
+   </PropertyGroup>
+ 
+diff --git a/src/Microsoft.DotNet.PackageTesting/build/Microsoft.DotNet.PackageTesting.props b/src/Microsoft.DotNet.PackageTesting/build/Microsoft.DotNet.PackageTesting.props
+index 82850655..394ed5cc 100644
+--- a/src/Microsoft.DotNet.PackageTesting/build/Microsoft.DotNet.PackageTesting.props
++++ b/src/Microsoft.DotNet.PackageTesting/build/Microsoft.DotNet.PackageTesting.props
+@@ -3,7 +3,7 @@
+ 
+   <PropertyGroup>
+     <DotNetPackageTestingAssembly Condition="'$(MSBuildRuntimeType)' != 'Core'">$(MSBuildThisFileDirectory)..\tools\net472\Microsoft.DotNet.PackageTesting.dll</DotNetPackageTestingAssembly>
+-    <DotNetPackageTestingAssembly Condition="'$(MSBuildRuntimeType)' == 'Core'">$(MSBuildThisFileDirectory)..\tools\net8.0\Microsoft.DotNet.PackageTesting.dll</DotNetPackageTestingAssembly>
++    <DotNetPackageTestingAssembly Condition="'$(MSBuildRuntimeType)' == 'Core'">$(MSBuildThisFileDirectory)..\tools\net9.0\Microsoft.DotNet.PackageTesting.dll</DotNetPackageTestingAssembly>
+   </PropertyGroup>
+ 
+   <UsingTask TaskName="GetCompatiblePackageTargetFrameworks" AssemblyFile="$(DotNetPackageTestingAssembly)" />
+diff --git a/src/Microsoft.DotNet.SharedFramework.Sdk/sdk/Sdk.props b/src/Microsoft.DotNet.SharedFramework.Sdk/sdk/Sdk.props
+index 44951b96..77176b15 100644
+--- a/src/Microsoft.DotNet.SharedFramework.Sdk/sdk/Sdk.props
++++ b/src/Microsoft.DotNet.SharedFramework.Sdk/sdk/Sdk.props
+@@ -9,7 +9,7 @@
+   -->
+ 
+   <PropertyGroup Condition="'$(DotNetSharedFrameworkTaskDir)' == ''">
+-    <DotNetSharedFrameworkTaskDir Condition="'$(MSBuildRuntimeType)' == 'core'">$(MSBuildThisFileDirectory)../tools/net8.0/</DotNetSharedFrameworkTaskDir>
++    <DotNetSharedFrameworkTaskDir Condition="'$(MSBuildRuntimeType)' == 'core'">$(MSBuildThisFileDirectory)../tools/net9.0/</DotNetSharedFrameworkTaskDir>
+     <DotNetSharedFrameworkTaskDir Condition="'$(MSBuildRuntimeType)' != 'core'">$(MSBuildThisFileDirectory)../tools/net472/</DotNetSharedFrameworkTaskDir>
+   </PropertyGroup>
+ 
+diff --git a/src/Microsoft.DotNet.SignTool/build/Microsoft.DotNet.SignTool.props b/src/Microsoft.DotNet.SignTool/build/Microsoft.DotNet.SignTool.props
+index 369cb60a..3522d8c5 100644
+--- a/src/Microsoft.DotNet.SignTool/build/Microsoft.DotNet.SignTool.props
++++ b/src/Microsoft.DotNet.SignTool/build/Microsoft.DotNet.SignTool.props
+@@ -2,7 +2,7 @@
+ <Project>
+ 
+   <PropertyGroup>
+-    <MicrosoftDotNetSignToolTaskAssembly Condition="'$(MSBuildRuntimeType)' == 'Core'">$(MSBuildThisFileDirectory)..\lib\net8.0\Microsoft.DotNet.SignTool.dll</MicrosoftDotNetSignToolTaskAssembly>
++    <MicrosoftDotNetSignToolTaskAssembly Condition="'$(MSBuildRuntimeType)' == 'Core'">$(MSBuildThisFileDirectory)..\lib\net9.0\Microsoft.DotNet.SignTool.dll</MicrosoftDotNetSignToolTaskAssembly>
+     <MicrosoftDotNetSignToolTaskAssembly Condition="'$(MSBuildRuntimeType)' != 'Core'">$(MSBuildThisFileDirectory)..\lib\net472\Microsoft.DotNet.SignTool.dll</MicrosoftDotNetSignToolTaskAssembly>
+   </PropertyGroup>
+ 
+diff --git a/src/Microsoft.DotNet.SourceBuild/tasks/build/Microsoft.DotNet.SourceBuild.Tasks.props b/src/Microsoft.DotNet.SourceBuild/tasks/build/Microsoft.DotNet.SourceBuild.Tasks.props
+index 9dc4c6cc..a49ee2b6 100644
+--- a/src/Microsoft.DotNet.SourceBuild/tasks/build/Microsoft.DotNet.SourceBuild.Tasks.props
++++ b/src/Microsoft.DotNet.SourceBuild/tasks/build/Microsoft.DotNet.SourceBuild.Tasks.props
+@@ -2,7 +2,7 @@
+ <Project>
+ 
+   <PropertyGroup>
+-    <MicrosoftDotNetSourceBuildTasksAssembly Condition="'$(MSBuildRuntimeType)' == 'core'">$(MSBuildThisFileDirectory)..\tools\net8.0\$(MSBuildThisFileName).dll</MicrosoftDotNetSourceBuildTasksAssembly>
++    <MicrosoftDotNetSourceBuildTasksAssembly Condition="'$(MSBuildRuntimeType)' == 'core'">$(MSBuildThisFileDirectory)..\tools\net9.0\$(MSBuildThisFileName).dll</MicrosoftDotNetSourceBuildTasksAssembly>
+     <MicrosoftDotNetSourceBuildTasksAssembly Condition="'$(MSBuildRuntimeType)' != 'core'">$(MSBuildThisFileDirectory)..\tools\net472\$(MSBuildThisFileName).dll</MicrosoftDotNetSourceBuildTasksAssembly>
+   </PropertyGroup>
+ 
+diff --git a/src/Microsoft.DotNet.SwaggerGenerator/Microsoft.DotNet.SwaggerGenerator.MSBuild/build/Microsoft.DotNet.SwaggerGenerator.MSBuild.props b/src/Microsoft.DotNet.SwaggerGenerator/Microsoft.DotNet.SwaggerGenerator.MSBuild/build/Microsoft.DotNet.SwaggerGenerator.MSBuild.props
+index 5362d800..1ae4e21c 100644
+--- a/src/Microsoft.DotNet.SwaggerGenerator/Microsoft.DotNet.SwaggerGenerator.MSBuild/build/Microsoft.DotNet.SwaggerGenerator.MSBuild.props
++++ b/src/Microsoft.DotNet.SwaggerGenerator/Microsoft.DotNet.SwaggerGenerator.MSBuild/build/Microsoft.DotNet.SwaggerGenerator.MSBuild.props
+@@ -2,7 +2,7 @@
+ <Project>
+ 
+   <PropertyGroup Condition="'$(MicrosoftDotNetSwaggerGeneratorMSBuildTasksAssembly)' == ''">
+-    <MicrosoftDotNetSwaggerGeneratorMSBuildTasksAssembly Condition="'$(MSBuildRuntimeType)' == 'Core'">$(MSBuildThisFileDirectory)../tools/net8.0/Microsoft.DotNet.SwaggerGenerator.MSBuild.dll</MicrosoftDotNetSwaggerGeneratorMSBuildTasksAssembly>
++    <MicrosoftDotNetSwaggerGeneratorMSBuildTasksAssembly Condition="'$(MSBuildRuntimeType)' == 'Core'">$(MSBuildThisFileDirectory)../tools/net9.0/Microsoft.DotNet.SwaggerGenerator.MSBuild.dll</MicrosoftDotNetSwaggerGeneratorMSBuildTasksAssembly>
+     <MicrosoftDotNetSwaggerGeneratorMSBuildTasksAssembly Condition="'$(MSBuildRuntimeType)' != 'Core'">$(MSBuildThisFileDirectory)../tools/net472/Microsoft.DotNet.SwaggerGenerator.MSBuild.dll</MicrosoftDotNetSwaggerGeneratorMSBuildTasksAssembly>
+   </PropertyGroup>
+ 
+diff --git a/src/Microsoft.DotNet.XUnitConsoleRunner/src/build/Microsoft.DotNet.XUnitConsoleRunner.props b/src/Microsoft.DotNet.XUnitConsoleRunner/src/build/Microsoft.DotNet.XUnitConsoleRunner.props
+index 09142a05..0af5cf87 100644
+--- a/src/Microsoft.DotNet.XUnitConsoleRunner/src/build/Microsoft.DotNet.XUnitConsoleRunner.props
++++ b/src/Microsoft.DotNet.XUnitConsoleRunner/src/build/Microsoft.DotNet.XUnitConsoleRunner.props
+@@ -2,7 +2,7 @@
+ <Project>
+ 
+   <PropertyGroup>
+-    <XunitConsoleNetCore21AppPath>$(MSBuildThisFileDirectory)..\tools\net8.0\xunit.console.dll</XunitConsoleNetCore21AppPath>
++    <XunitConsoleNetCore21AppPath>$(MSBuildThisFileDirectory)..\tools\net9.0\xunit.console.dll</XunitConsoleNetCore21AppPath>
+   </PropertyGroup>
+ 
+ </Project>
+diff --git a/src/Microsoft.DotNet.XliffTasks/build/Microsoft.DotNet.XliffTasks.targets b/src/Microsoft.DotNet.XliffTasks/build/Microsoft.DotNet.XliffTasks.targets
+index 2bce08cd..d45f1cb2 100644
+--- a/src/Microsoft.DotNet.XliffTasks/build/Microsoft.DotNet.XliffTasks.targets
++++ b/src/Microsoft.DotNet.XliffTasks/build/Microsoft.DotNet.XliffTasks.targets
+@@ -2,7 +2,7 @@
+ <Project>
+ 
+   <PropertyGroup>
+-    <XliffTasksDirectory Condition="'$(XliffTasksDirectory)' == '' and '$(MSBuildRuntimeType)' == 'Core'">$(MSBuildThisFileDirectory)..\tools\net8.0\</XliffTasksDirectory>
++    <XliffTasksDirectory Condition="'$(XliffTasksDirectory)' == '' and '$(MSBuildRuntimeType)' == 'Core'">$(MSBuildThisFileDirectory)..\tools\net9.0\</XliffTasksDirectory>
+     <XliffTasksDirectory Condition="'$(XliffTasksDirectory)' == '' and '$(MSBuildRuntimeType)' != 'Core'">$(MSBuildThisFileDirectory)..\tools\net472\</XliffTasksDirectory>
+     <XliffTasksAssembly>$(XliffTasksDirectory)Microsoft.DotNet.XliffTasks.dll</XliffTasksAssembly>
+   </PropertyGroup>
diff --git a/src/SourceBuild/patches/arcade/0002-Target-net9.0-for-arcade-projects.patch b/src/SourceBuild/patches/arcade/0002-Target-net9.0-for-arcade-projects.patch
new file mode 100644
index 000000000..9dd18d1c6
--- /dev/null
+++ b/src/SourceBuild/patches/arcade/0002-Target-net9.0-for-arcade-projects.patch
@@ -0,0 +1,22 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Matt Thalman <mthalman@microsoft.com>
+Date: Thu, 16 Nov 2023 14:48:18 -0600
+Subject: [PATCH] Target net9.0 for arcade projects
+
+Backport: https://github.com/dotnet/source-build/issues/3743
+---
+ Directory.Build.props | 1 +
+ 1 file changed, 1 insertion(+)
+
+diff --git a/Directory.Build.props b/Directory.Build.props
+index 32befcfc..2285cc5d 100644
+--- a/Directory.Build.props
++++ b/Directory.Build.props
+@@ -9,6 +9,7 @@
+     <DebugType>embedded</DebugType>
+     <DebugSymbols>true</DebugSymbols>
+     <LangVersion>Latest</LangVersion>
++    <NetCurrent>net9.0</NetCurrent>
+ 
+     <!--
+       Tools and packages produced by this repository support infrastructure and are not shipping on NuGet or via any other official channel.
diff --git a/src/SourceBuild/patches/arcade/0003-Update-NetCurrent-to-net9.0-in-Arcade-SDK.patch b/src/SourceBuild/patches/arcade/0003-Update-NetCurrent-to-net9.0-in-Arcade-SDK.patch
new file mode 100644
index 000000000..55498b3c7
--- /dev/null
+++ b/src/SourceBuild/patches/arcade/0003-Update-NetCurrent-to-net9.0-in-Arcade-SDK.patch
@@ -0,0 +1,28 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Matt Thalman <mthalman@microsoft.com>
+Date: Thu, 16 Nov 2023 14:49:33 -0600
+Subject: [PATCH] Update NetCurrent to net9.0 in Arcade SDK
+
+Backport: https://github.com/dotnet/source-build/issues/3743
+---
+ .../tools/TargetFrameworkDefaults.props                       | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+diff --git a/src/Microsoft.DotNet.Arcade.Sdk/tools/TargetFrameworkDefaults.props b/src/Microsoft.DotNet.Arcade.Sdk/tools/TargetFrameworkDefaults.props
+index b7071a30..0afe2322 100644
+--- a/src/Microsoft.DotNet.Arcade.Sdk/tools/TargetFrameworkDefaults.props
++++ b/src/Microsoft.DotNet.Arcade.Sdk/tools/TargetFrameworkDefaults.props
+@@ -10,11 +10,11 @@
+ 
+   <PropertyGroup>
+     <!-- The TFM of the major release of .NET that the Arcade SDK aligns with. -->
+-    <NetCurrent>net8.0</NetCurrent>
++    <NetCurrent>net9.0</NetCurrent>
+ 
+     <!-- The previously released version of .NET.
+          Undefined when NetMinimum and NetPrevious are identical. -->
+-    <NetPrevious>net7.0</NetPrevious>
++    <NetPrevious>net8.0</NetPrevious>
+ 
+     <!-- Lowest supported version of .NET at the time of the release of NetCurrent.
+          E.g. net6.0 when NetCurrent is net8.0. -->
diff --git a/src/SourceBuild/patches/nuget-client/0001-Target-net9.0.patch b/src/SourceBuild/patches/nuget-client/0001-Target-net9.0.patch
new file mode 100644
index 000000000..f3707da91
--- /dev/null
+++ b/src/SourceBuild/patches/nuget-client/0001-Target-net9.0.patch
@@ -0,0 +1,65 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Matt Thalman <mthalman@microsoft.com>
+Date: Thu, 16 Nov 2023 14:56:46 -0600
+Subject: [PATCH] Target net9.0
+
+Backport: https://github.com/NuGet/Home/issues/13018
+---
+ build/common.project.props                                      | 2 +-
+ build/common.targets                                            | 2 +-
+ src/NuGet.Core/NuGet.Configuration/NuGet.Configuration.csproj   | 2 +-
+ .../NuGet.PackageManagement/NuGet.PackageManagement.csproj      | 2 +-
+ 4 files changed, 4 insertions(+), 4 deletions(-)
+
+diff --git a/build/common.project.props b/build/common.project.props
+index 17f9811a1..34069f5d6 100644
+--- a/build/common.project.props
++++ b/build/common.project.props
+@@ -12,7 +12,7 @@
+     <NETFXTargetFrameworkVersion>v4.7.2</NETFXTargetFrameworkVersion>
+     <NETFXTargetFramework>net472</NETFXTargetFramework>
+     <NETCoreTargetFramework>netcoreapp3.1</NETCoreTargetFramework>
+-    <NETCoreTargetFramework Condition="'$(DotNetBuildFromSource)' == 'true'">net8.0</NETCoreTargetFramework>
++    <NETCoreTargetFramework Condition="'$(DotNetBuildFromSource)' == 'true'">net9.0</NETCoreTargetFramework>
+     <NETCoreTestTargetFrameworks>net8.0</NETCoreTestTargetFrameworks>
+     <NetStandardVersion>netstandard2.0</NetStandardVersion>
+     <TargetFrameworksExe>$(NETFXTargetFramework);$(NETCoreTargetFramework)</TargetFrameworksExe>
+diff --git a/build/common.targets b/build/common.targets
+index 08974ae7a..f07f90832 100644
+--- a/build/common.targets
++++ b/build/common.targets
+@@ -6,7 +6,7 @@
+     <IsDesktop>true</IsDesktop>
+   </PropertyGroup>
+ 
+-  <PropertyGroup Condition=" $(TargetFramework.StartsWith('netcoreapp')) OR $(TargetFramework.StartsWith('netstandard')) OR $(TargetFramework.StartsWith('net6')) OR $(TargetFramework.StartsWith('net7'))  OR $(TargetFramework.StartsWith('net8')) ">
++  <PropertyGroup Condition=" $(TargetFramework.StartsWith('netcoreapp')) OR $(TargetFramework.StartsWith('netstandard')) OR $(TargetFramework.StartsWith('net6')) OR $(TargetFramework.StartsWith('net7'))  OR $(TargetFramework.StartsWith('net8')) OR $(TargetFramework.StartsWith('net9')) ">
+     <DefineConstants>$(DefineConstants);IS_CORECLR</DefineConstants>
+     <IsCore>true</IsCore>
+   </PropertyGroup>
+diff --git a/src/NuGet.Core/NuGet.Configuration/NuGet.Configuration.csproj b/src/NuGet.Core/NuGet.Configuration/NuGet.Configuration.csproj
+index eea152eb6..74dd4905a 100644
+--- a/src/NuGet.Core/NuGet.Configuration/NuGet.Configuration.csproj
++++ b/src/NuGet.Core/NuGet.Configuration/NuGet.Configuration.csproj
+@@ -26,7 +26,7 @@
+     <Reference Include="System.Xml.Linq" />
+   </ItemGroup>
+ 
+-  <ItemGroup Condition=" '$(TargetFramework)' == '$(NetStandardVersion)' or '$(TargetFramework)' == 'net7.0' or '$(TargetFramework)' == 'net8.0' ">
++  <ItemGroup Condition=" '$(TargetFramework)' == '$(NetStandardVersion)' or '$(TargetFramework)' == 'net7.0' or '$(TargetFramework)' == 'net8.0' or '$(TargetFramework)' == 'net9.0' ">
+     <PackageReference Include="System.Security.Cryptography.ProtectedData" />
+   </ItemGroup>
+ 
+diff --git a/src/NuGet.Core/NuGet.PackageManagement/NuGet.PackageManagement.csproj b/src/NuGet.Core/NuGet.PackageManagement/NuGet.PackageManagement.csproj
+index 38658b221..740dd2bf7 100644
+--- a/src/NuGet.Core/NuGet.PackageManagement/NuGet.PackageManagement.csproj
++++ b/src/NuGet.Core/NuGet.PackageManagement/NuGet.PackageManagement.csproj
+@@ -32,7 +32,7 @@
+     <Reference Include="System.Net.Http" />
+   </ItemGroup>
+ 
+-  <ItemGroup Condition=" '$(TargetFramework)' == '$(NetStandardVersion)' or '$(TargetFramework)' == 'net7.0' or '$(TargetFramework)' == 'net8.0' ">
++  <ItemGroup Condition=" '$(TargetFramework)' == '$(NetStandardVersion)' or '$(TargetFramework)' == 'net7.0' or '$(TargetFramework)' == 'net8.0' or '$(TargetFramework)' == 'net9.0' ">
+     <PackageReference Include="System.ComponentModel.Composition" />
+   </ItemGroup>
+