Quinterro, what is the color of the label on the OS9 CD? If it's white, it should work on most Macs. If it's grey or some other color, it could only be used for specific models. It could be that, or the disc is screwed up, or the OS version on track 0 is not meeting the minimum requirements supported by the machine. It's hard to say, but let's find out what color the discs are first.

EDIT: Oh, forgot to mention. Try having say about 64 MB of RAM installed when you boot off the CD. Also, try a different CD/DVD drive. It possibly could be that the drive is not spinning the disc or needs some cleaning or the laser isn't working. Just some additional thoughts.

73s 8)