A lot depends on the resort you'll be at. If you're at Pop, or another value resort, your luggage could take a very long time!! The value resort luggage delivery system is slow at best. So, late at night, it's downright unreliable!! If you arrive at your resort at 10-10:30, your luggage may not get to your room. The value resorts don't do a lot of luggage delivery past 10pm..if they do, it's very sporadic.
If you are at a deluxe resort, or DVC, then your bags should get to your room within 3 hrs of resort checkin...could easily be sooner rather than later.
If it were me, and I was arriving at 9pm?? I wouldn't tag my bags, and I would then go to baggage claim and get them myself. Yes, it would add about 20 mins to my overall time, but I would have them with me, and I could unpack and go to bed!!