If you arrive at 7pm, you should be at your resort no later than 8:30...probably a bit sooner. Your luggage can be expected up to three hours after resort checkin..so could be as late as 11:30pm. But, it will most likely arrive sooner than that.
A lot depends on the resort you are staying at. The deluxe resorts seem to get your bags to you more quickly than other resorts. The moderate resorts are pretty good about not having you wait for a long time. But Pop can be awful. They make less frequent baggage delivery runs..they seem to do it every hour or so...regardless of how much they have sitting there. Pop is the only resort I've had a long wait for my checked bags to arrive at.
In all reality, you may very well have your bags by 10-10:30. But, to be on the safe side, pack that carryon bag properly..pj's for the night, change of clothes for the next day...just in case.
If you decide to grab your own bags from baggage claim at MCO, you don't tag them with they yellow DME luggage tags! Leave those off, go to baggage claim and get the bags and then head down to level 1 and DME. Your bags will be stowed underneath your bus. It will add about 20 or so mins to your travel time but at least you'll have your bags with you. You can get unpacked and settled in and then get a good night's sleep.