9.2.2 install DVD is only meant for the system it shipped with. The Pismo is also known as the Powerbook Firewire on this article:
As such you can only use the Powerbook Firewire installer for 9.0.2, or the retail installers for 9.0.4, 9.1, or 9.2.1 to install 9 on your Pismo.
The startup manager may help if you have the right disc
Use the Option key, when possible instead of 'C' key to boot discs
If you have the right discs, and the Option key does not work, your computer may need a replacement PRAM (CMOS) battery for the main logic board (motherboard). This is different than the battery that goes in the battery bay of the computer.