OS9 startup problems from OSX 10.3.9

Hi! Against my better judgement, I recently installed an update to 10.3.9 on my desktop G4 (from 10.3). I mainly use my computer for music recording and use a program which is on an OS 9 partition. Since the update, I am unable to get the machine to boot up in OS 9 from specifying the startup disk in the System Preferences. However, I can boot the computer up in OS 9 from holding down the option key.

I thought that I could get around this by resetting the NVRAM - to no avail, unfortunately. Any ideas and (sorry for being naive) would I be doing any harm by continuing to access OS9 in this way?

Many thanks in advance,
John

If you are able to start up in OS 9 using the option key, have you tried to reset the startup disk in OS 9?

http://docs.info.apple.com/article.html?artnum=106667#sec2