How can I save/export a JavaScript (JSX) file as an encrypted file (jsxbin) in VS code on MAC OS?

You could that without any extension apart from the "Adobe Extendscript Extension". I quote how to do that from the article linked below

"Export to JSXBin

You can export your .js and .jsx scripts to JSXBin by right-clicking the editor window of a .js or .jsx file and selecting Export As Binary.... A file name suggestion will be provided. If you proceed with the export, the results will be saved in the same directory as your currently opened file. You can enter a complete path for the output if desired.

The command string is extension.extendscript-debug.exportToJSXBin and there are no configurable command arguments."

https://marketplace.visualstudio.com/items?itemName=Adobe.extendscript-debug

-Manan

Install an extension "Text to JSXBIN" 

• Select created piece of code.
• Right click of the mouse and choose TextToJSXBIN
• Selected code will be converted to JSXBIN, put inside eval and original code will be commented.
• Save File