<TargetFrameworks>net9.0;net8.0</TargetFrameworks> in project file."launchConfigurationId": "TargetFramework=net8.0" in launch config file.net9.0 and net8.0 got build as I can see them in their respective directories that is debug\net9.0 and debug\net8.0. But I am not sure that which one ends up running.

