To unlock 'What a Hit,Son!' you must score with any dipping volley.
I went into this achievement thinking the same as you....volley or half volley the ball, make sure the trajectory goes up before going down again, and then having it score.
However, it doesn't seem to be the case. Not any volley will do however, but below is a video of the exact shot that popped my achievement, and to my visual eye it doesn't dip at all. Just go for a volley where you use your laces and not your side foot (side foot volley didn't pop for me, yet a lace volley did shortly after).
Hope this helps slightly, as it means you don't need to go for a super spectacular. Either way, the best method is a chip through ball (LB+Y) followed by a fairly powerful volley/half volley.