Mactracker says you can take the latest OS X release.
I entirely sympathize with how you feel. I felt the same way when upgrading from 9.0 to 9.2.
The only way to really look at this, is to go to the publisher of your software's website and check their compatability. Search Apple's forums and supports for known conflicts. If you're a graphic designer, ask other people in your industry what OS they use, and if they've encountered any problems upgrading.
If you're really not feeling confident about it, you could install (not upgrade) 9.2 on a separate drive, so that worse case scenario, you simply switch back to your 9.1 drive.
From my experience, when I had my ol' iMac DV SE 400, and updated from 9.1-9.2.2, I had no problems to speak of, but then, different situations entirely, of course, but it's nice to hear a happy ending
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