What G4 are you using? Not all G4's could boot OS 9. Also, not all OS 9 installs are bootable. Some OS 9 installs were only for Classic Mode. I'm guessing the G4 you are using is running OS X, and if there is OS 9 installed on it, it should run Classic Mode, which I would recommend anyway. As for your disk showing PC instead of the Blueprint icon, it's not becasue the disk is corrupt, it's because the Mac you stuck it in doesn't recognize Blueprint files, so it just assumes they are files for software that runs on a PC.