Unless you possess some special magical powers, you cannot "train past" the fact that 9mm recoils less than .40.
So What? A 44 magnum recoils more too. The point is can you handle the recoil? You can train to the point that you expect the blast and recoil of a Magnum, what is so difficult. In a real shooting you are not going to feel recoil, you are not going to consciously hear the gun in all probability. You will be loaded with adrenaline, like I said recoil is a range issue. The only time I can see it as an issue is if it hurts to shoot and the person will not shoot enough to become proficient.
I understand that anyone can shoot a 9mm faster than they can shoot a 40 in the same gun, so what?