Depends on how fast you can move towards either side. If you are fast enough to catch up to the ball, you can just wait (see Kamio vs Sengoku), but if not, the ball will just go past you. Jirou doesn't have great coverage to the sides from what we know, so he'd have to decide for a side before Kai hits, leaving an opening on the other side.
Akutsu hits after you move. Kai hits after you move. That's the similarity I was referring to. Of course Akutsu has other abilities on top of that that Kai is lacking.