The fact that you have tried accessing the disc on two different computers, neither of which is mounting the missing partition points to this as an issue with the disc rather than the computer.
Have you tried running disk first Aid? (boot your mac from your OSX install disc and on the first screen, choose Disc First Aid from one of the menus).
This should allow you examine and repair the disk (if first aid can figure out whats wrong).
Alos try rebuilding the desktop on your OS9 mac (ALT CMD during reboot) though I doubt this will work it’s always worth a try.