I'm not sure where ID keeps the scratch disk on Macs, but on Windows it's in the Temp directory in your user profile, so it wouldn't surprise me if it were someplace in your user library on the Mac, and there's no way to move it that I know of. Photoshop and Illustrator allow you to put your scratch disk naywhere you like.
ID does, though, allow you to move the recovery folder to a new location, and you should try that, too, before uninstalling. It's in the prefs.