How to replace PRAM battery in Power Mac 9600?

You need to remove the cover/retainer that snaps over the top of the battery holder. Using a very small screwdriver, insert its flat tip between the outside of the socket's positive metal contact and the battery retainer's end. Gently pry outward against the plastic retainer to unsnap it. You may need to do the same at the opposite end to completely pop it off. Once that's removed, you can actually grasp the battery by its sides and roll it up and out of the holder. Otherwise, insert the same small screwdriver under the lip on the outer rim of the battery's positive end, and pry/lift it out of the holder.

The battery retainer is a real "sight gag". It is vaguely C-shaped and has extra little hooks on its inside ends. The pressure must be applied outward, along it length. This site has a couple of photos of it, as well:

http://www.academ.com/info/macintosh/