9...Qxf4 is the main line, because why not take a pawn if White's going to leave them lying around.
9...Qh4+ is similar to the main line, in that the Black queen ends up on h3 via h4 in both lines, except without the bonus of having taken a pawn. A pawn is a pawn!
Wikipedia has related information at Ruy_Lopez#Schliemann_Defence:_3...f5 |