Pitchers most certainly have and do throw at a batter's head.
Extremely rarely. If you’re hitting someone on purpose, you do what Alex Wilson did. You drill him in the hip or thigh.
Betances was aiming high and inside. It wound up a little too high and a little too inside. But in a tie game, he’s going to hit someone on purpose? Not likely.
Notice that Wilson, who hit Frazier on purpose, got suspended. Kahnle and Betances did not.