I know it sounds insane and is REALLY frustrating, but don't rely on CM's for accurate info. about anything. Really, it's not even worth asking them anything as most of the time they give false info. Drives me nuts...if you don't know, just say you don't know and then seek other resources to find out the accurate info. It cannot be that hard, every other business/organization does it...
Anyways, yes buses start early enough for any early ADR's, no need for a cab and just in general if you have a question ask on here.