Okay - that means - you may not have the OS 9 drivers installed.
Back up all your important documents, etc. Then boot from the OS 9 CD and go to drive set up. From the menu select update drivers. Then quit Drive setup and go to the installer. A clean install means that it will rename your system folder as previous system folder. It should then install OS 9. When done, you should have OS 9 system folder. Now get the OS X cd and install that (boot from CD). You should then have all your OS X files still intact and both OS 9 and OS X on the drive.