Not sure if you managed to fix the issue with your Mac since last year but a maxed out 9600 with 1.5GB of RAM takes 4 minutes to complete the initial RAM test before switching on the screen. It may look like video is not working but it just takes that long before the computer actually starts booting after testing the RAM. I have the same issue with my 9500. You can disable the RAM test with MacOS 9. I think you need to press the Option key while opening the Memory control panel.

I can also add that if you force reboot the Mac during the RAM test (Ctrl Cmd Power) it won't proceed with the RAM test on the second boot. RAM test is only triggered on a cold boot. I am not sure if this can damage the RAM though and this is a trick impatient me sometimes uses for fast booting System 7.

I would love to find a way to disable RAM test when booting System 7.

It doesn't damage the RAM to do that. The ANS is the same way and I routinely do a "double reboot" to skip the Long RAM test, which on that machine can take a couple minutes fully loaded as well.