I'm trying to get rid of OS9, but when I try to drag the system folder to the trash, I get the message that it can't be deleted because the system needs the folder. How do I get it to the trash and then to actually empty the trash? The folder is not locked.

One way, using an admin account:

Verify that you have a good backup. Terminal commands, especially "rm" can be fatal to your system.

Open the Applications:Utilities:Terminal

cd /
sudo rm -rf 'System Folder'

If you get a "file busy" error, try

cd /
sudo mv 'System Folder' blah

Then, after reboot,

cd /
sudo rm -rf blah