What language is OS 9 written in?

It's not the OS, but Google Earth is must-have functionality for me that I can't get while running OS 9. Of course now I can't get it in Panther either, and that will be what drives me to upgrade to Tiger.

I waited three years after OS X was introduced to use it. I just couldn't bear the idea that after 20 years of using Macs, I'd have no clue how to solve problems in OS X. Nor could I imagine what a non-issue that would turn out to be when I finally dipped my toe in (at Jaguar, soon upgraded to Panther).

Bah, Google Earth, of course. Maybe one of the reasons I bought an iPod Touch, just so I wouldn't have to switch from Panther to Tiger on my MDD.
I had thought that the images available in Google Earth were available under Panther with Google Maps (had the Google Maps car outside my house yesterday for 20 minutes taking street pictures, hopefully all my playing about outside with my 19-month son will bring fame, even if they fuzz my face).
Likewise, my 20+ years of Unix is largely unrequired looking after Mac OSX, although it does help with programming projects.

Yeah, if you could find a disassembler that would do it, which you might not.

Legally, you have to read the EULA that came with OS 9 to find out.