Can't boot from OS 9.0 CD

[Kenneth Strain]

I want to to a system install of OS 9.0 onto a firewire drive that will end
up in my cube, and it says I have to boot from the CD.  Try as I might,
despite switching to the Mac OS All set of extensions, turning off Techtool
System Protection, and following instructions, my computer refuses to boot
from the CD when I hold down "C".  Is OS 9.0 incompatible with the Cube?

-Ken