Step 1: Boot into OS 9
Step 2: In the Energy Saver control panel, set it to start up whenever you want. That should be pretty straight forward.
Step 3: Open the Startup Disk control panel. Set it to start up to your Mac OS X partition.
Step 4(optional): Back in OS X, go into System Prefs and the Login. Tell it to login automatically.
That'll start up your computer into OS X at the designated time, and log you in.