Hey, I've been able to make the project properties square, but there isn't a corresponding render template to make the video square, or an option to make a custom template.
In the basic version you are stuck to the given render presets. If there is no square frame render preset, no (direct) way to do (except you'd accept black borders).
I don't have VMS 14 basic version so I can't check it there. But I have that one of VMS 16. There it is possible to make a square project through Project/Properties that is able to render it also square. Look at the screenshot
@j-v shows you an example in the basic Movie Studio 16 here. The Platinum version is recommended as you can customize render templates there and the price difference is rather negligible. Test with the free trial, available here. Rendering in the trial is restricted to a project less than two minutes though.
Just to add two workarounds for the basic version:
You could also render a squeezed version of your cropped footage and then use another renderer just like FFmpeg to render a square version of the Movie Studio output.
You could use a Vegas render template file generated elsewhere (from another person or from the Platinum or Vegas Pro demo version) which you then copy to the Movie Studio Render Templates folder (User/Name/App Data/Roaming/).