I'm pretty sure it would be number 2, since her bear form gives you a "+3" modifier to her current health and not a separate "9" HP. So reverting back removes your max health bonus, but leaves the wounds untouched, killing you. I would also play this way. I don't see an effect that would let you remove 3 wounds.
Doesn't mean I'm right, though. That said, from a balancing perspective building in a 3 HP heal to Bear Form seems like it would make it very strong.