Two problems related to front air bag have been reported for the 2009 Toyota Prius. The most recently reported issues are listed below.
I own a Prius 2009. I was involved in an accident in which a truck run a red light, broadsided a vehicle at the intersection. This vehicle spun and hit the right front part of my car. The problem is that the driver airbag deployed about 2 min after the hit, but the airbag was torn and the inflation gas leaked into the cabin. The passenger bag was not deployed. I was alone in the car and was not injured. I have reported the incident to Toyota.
2009 Toyota Prius was hit from behind and pushed into the vehicle in front. At no time did the seat belts catch nor did the airbags deploy. My daughter's face collided with the dashboard due to the seat belts not working and no airbag deployment. So far Toyota says that there is nothing to fix, the car performed as it was designed to.