I'm using an 9600 running OS9 with a 22" Viewsonic LCD. I have a G3 card and I think a Radeon 7000 or Rage 128. I've changed the cards a few times.

I think the only problem I've had is accidentally setting the refresh rate to something the LCD won't do. Try booting with extensions off and seeing if that'll give you anything. If it does then you could try deleting your monitor preferences and rebooting.