Where can I get a mac OS 9 system folder?

My younger brother and sister just gave my kids a bunch of their old games that were written for OS 9. My understanding was that I’d be able to run them in “classic mode” on our old PPC mac running Tiger. However, when it starts up it asks me to locate the OS 9 system folder (which it doesn’t seem to have). I don’t have any install disks because I bought the computer at an auction from a local elementary school. I only have Leopard install disks, which don’t seem to have any “classic mode” support at all.