Terry, based on the error message provided, i.e. "About Widget Demo", I assumed that the poster was not using IDLE here. But we can't tell without more input.

"when I run 3.9 test.pythoninfo, I am asked to install gcc tools and maybe xcode.  Is this expected?"

When doing Python development on macOS, you will need to have the Apple-supplied development tools installed and ones appropriate for the macOS release. As the Developer's Guide explains (https://devguide.python.org/setup/#macos-and-os-x), the necessary tools are available if you install the full Xcode development environment from the Mac App Store but that's a big download and most of it is not necessary for just cpython work. If you haven't already downloaded Xcode, then the first time you (or, in this case test.pythoninfo) try to use one of the development tools from the terminal shell command line, macOS offers to download and install a lightweight subset of what's available in Xcode, called the Command Line Tools.  You can also force the installation of the CLT by using "xcode-select --install". Once the CLT are installed, they are normally automatically updated as needed by the macOS Software Update process.