Jieunni, the PC9 has a light weight Martin baker ejection seat, in the CT4 you can open the canopy and jump out.
As for the PC12, it is designed to be crash worthy were as the PC9 was designed with the intention to eject rather than force land. Once the decision to eject is made, if you have any control over the aircrafts flight path the impact point of the aircraft is always a consideration. Common sense and good airmanship really.
The other major advantage of a bang seat is it works after a mid air as the roulettes have proved. The risk of a mid air was always a major concern in congested training airspace.
Finally they may look a bit Nancy to you using respirators at the crash site but the RAAF is justifiably gun shy on OH&S. They broke a lot of people working on F111s without proper PPE. If people aren't cautious were you work that doesn't make it right.