Switching from OS X to OS 9

I was trying to switch from OS X to OS 9 on my G4 and when it rebooted all that came up was a gray screen with a small floppy disk icon in the middle. There's a flashing ? on the icon. We've tried rebooting holding 'option' & X down and get the same thing. We rebooted holding 'alt' down and got a blue screen with the harddrive icon in the middle with a 'refresh' button to the lower left and a right arrow button to the lower right. From here we can't do anything. How do I get it switched back to OS X??
Thanks!