I always get EBCI when flying home from WDW. Why? I hate worrying about checking in at the 24 hr mark. It's worth the small addtl cost to not worry about it.
Then, I head to RAC first thing in the morning, hand my bags off, get my boarding passes, and go about my day.
You would have to have your bags checked, boarding passes in hand, walking away from the RAC counter no later than 8:15. You must be finished checking your bags no less than 3 hrs before flight departure time.