i know if you have the available ram you can adjust up the max memory partition. which will give you a little bit of a speedup. you can also install flash player and shockwave and a few other things to get to play somewhat correctly online.

other than iCab, wamcom mozilla 1.3.1 is the best you can get for a web browser for Mac OS 9.x. i also think you can download the source code so you can compile it if you want to.

http://wamcom.org/