I just had the Power Steering fixed and now the steering wheel is 90 degrees off, the horn doesn’t work and the AirBag light is on.

Whoever put the rack in turned the steering wheel while the rack was out and broke the clock spring in the steering column. The clock spring is a part that has a coil inside of it allowing the steering wheel to be hard wired to the vehicle electrical systems, the air bag, horn and any switches on the steering wheel will be wire through this part. When the steering column was unhooked from the steering rack the wheel was turned to far and broke the coil in the clock spring and now the airbag light is on because of the open circuit to the air bag module and the horn is dead for the same reason. As for the wheel mis alignment, poor quality workmanship, find a new mechanic.