Question: if you have safe on, should the hellfire still hit the target

[Ramstein]

Question: if you have safe on, should the hellfire still hit the target, just not detonate?

[Raptor9]

If the A/S button is set to SAFE, the missiles (or any weapon) and the laser won't fire.

If you set the A/S button to SAFE after a missile is launched, you won't be able to fire the laser; so if you are using the laser-guided missile variants the missile won't hit the target anyway.

[NeedzWD40]

Once the missile is launched, a sequence of events is triggered that arms the missile if it meets a set of criteria -- none of which involve seeker acquisition. At any point past this, the warhead is live and will go off if the missile contacts something. So if you launch on a buddy laze and then safe up your aircraft, the missile will hit and make boom. Conversely, if buddy laze goes off (or your own), missile will make boom somewhere else.