Big question is how are you pl;anning on getting to the MK?
If you are seated promptly, figure dinner and entertainment to be 1.5 hours or so. So you should be on your way before 9 to get to MK. I would plan on leaving through the International Gateway and heading over to the BC to catch a bus to the MK. Depending on how your luck runs with buses, you may wait up to 20 minutes for a bus. Let's say you arrive at the MK at 9:30. Then you still have to get through the turnstiles and grab a spot.
I think I would push back my ADR to 6. This way you can enjoy a nice leisurely dinner and entertainment at Marrakesh without feeling the time pressure.
Have fun!