Yes, at that time I do think the pass will be useful. If you got a room at one of the three that offer express with the room you don't have to stay there. You could check in at 6am print your express and be in the park for early entry (also included with the room). Often the cost of the room is less than the cost of buying the express passes plus you get early entry to beat the crowds to the Harry Potter areas. Worth checking on the price for a room if you have 3 - 5 in your party. Try the Royal Pacific, it should be the least expensive for a standard room.
You don't even have to unlock the door to the room you can print your express pass in the lobby after checkin.