We use Uber all the time, and we are locals, put in the address of Bay Lake or the Contemporary. That intersection is beyond busy and I am not sure if they will drop you there. Once you are in the car, tell the driver where you want to get dropped off. We have walked from the Contemporary over to MK, not a bad walk about 10 minutes.
As a suggestion you might want to get dropped off at one of the monorail resort, and just take the monorail around to MK.