2♠ only says " 9HCP".
I think this is a incomplete definition, its true meanings is 4-card ♠ with 9hcp, invitational, non-forcing. So it can cause several related problems :
- 2nt says " Invitational to 3nt game --- 2-5♣,2-5♦,4-5♥,2-4♠,15-17hcp,18-TPs."
Here we should note 2-4♠, 4♠ is impossible. That's to say that if opener really holds 4-card ♠, opener only can choose pass or 4♠ instead of rebid-2nt.
- 3nt says " 2-5♣,2-5♦,4-5♥,2-4♠,16-17hcp,18-TPs."
Here we should note 2-4♠, 4♠ is usually impossible.
So I suggest that the 2♠ definition should be 4-card ♠ with 9hcp, invitational, non-forcing.