Turn everything off w/ extensions manager, then when X starts up Classic it'll say something like "Classic requires missing resources, should I add them?" Say OK, then you'll have the absolute bare minimum required to run Classic. Now, just add extensions whenever you find a need for them on a case by case basis.
Because I always forget to change the startup set when I reboot into 9, I have two copies of 9, one for classic on my X partition and the "real" 9 on its own partition.
...switch off Appletalk in the Chooser, and disable the 'recent items' option in Apple Menu Items. And then rebuild the Classic Desktop from System Preferences>Classic>Advanced.
This has sped up the Classic launch time for me considerably. Also, I find it is faster if you launch it independently of a Classic app (ie it is quicker to start Classic, then launch Photoshop, than it is to launch photoshop and have Classic boot then). doing this means you are less likely to experience the 'No Classic Menu Bar' bug