you cannot boot into OS9 on a 12 inch powerbook. You can delete the applications folder for os9, but its not very big and i would recommend leaving it. it isnt hurting anything. but os 9 wont work on a 12 or 17 powerbook.
also you can start up classic in system preferences, you cen even configure it to auto load classic when you boot into X.
so you dont have to open an app, it can be done in system prefs.