Don't hold your breath on that one - Megabus is point A to B and nothing in between (other than connections) and most, if not all, drivers I know off won't entertain requests for stopping elsewhere. I know I don't as it is just asking for trouble, before you know it you have people asking off at every stop on the way in to town.
In my experience the bus will probably breakdown at the Kessock roundabout anyway as their buses dont seem to do all of the A9 in one go !!!!!!!