Well as they tend to be mounted very close to the wall vibration shouldn't be anywhere as much as in the middle of the ceiling. You could always do a test with a pin and some string to see if it twitches while you get your teenager to jump around upstairs
There are wall mounting options out there that let you mount it high up the wall and upside down as if it was ceiling mounted. Google "Vogel projector wall mount" for the one I was thinking of or "projector wall mount" for alternatives
People have also built shelves and mounted them on the underside of the shelf or put it on the shelf if the lens shift is good enough.