If a mountlist (CF0) is in the Devs/DOSDrivers drawer, it should be automounted on the boot. Are you sure it isn't in the Storage/DOSDrivers drawer?
What SCSI controller do you have? Maybe it needs a bus rescan to find the device?
Or are you mixing up SCSI and PCMCIA? If you're just using the CF card with a CF-PCMCIA adapter in the PCMCIA slot of Amiga (no SCSI involved then) it should just appear on the desktop when plugged in if CD0 mountlist is in the Devs/DOSDrivers drawer. If it doesn't work automatically, check if your S:startup-sequence still contains the line "C:Mount >NIL: DEVS:DOSDrivers/~(#?.info)" or has it been removed for some reason.
