So many variables here. If you arrive, ontime, at 9pm, that means you won't be at your resort until about 10:30, possibly a bit sooner. So, if you arrive at 10:30, you can expect your bags to be delivered well after midnight!! And, add to that....depends on which resort you are staying at. The value resorts just don't do luggage delivery much later than 10pm. The moderates are a bit better, with the deluxes having the best luggage delivery service. BUT....there are no promises that your bags will get to you in a timely fashion. WDW can, and does, change it's policies without any notice.
So...with that in mind.....pack a carryon bag with anything you may need for the evening, and early the next morning. Then, when you arrive at your resort, tell them to please hold your luggage until the next morning. Stop at Bell Services/Luggage Assistence (depends on which resort you're at), and tell them the same thing. Then, when you get to your room, hang out the 'privacy please' hanger on your door. That way, if someone misses the note that you want your bags held, they won't disturb you!!! There should be a message on your phone, when you wake up, telling you that your bags are ready to be delivered.
Or, if you don't want to do all that, just don't tag your checked bags and get them yourself at baggage claim, and then bring them to the DME bus with you. Be prepared to tip the driver though.