Doubt a reliable 9mm lever could be built.
But you get about a 200 fps gain rifle over
pistol. And you would also gain a longer
Looking at your BBTI link, some of the loads tested (who shoots 90 gr 9x19?????) you got around 200 f/sec improvement going from a 5" barrel to an 18" ..... but the 147 gr Hydrashock had less than 80 f/sec improvement.....
I hear guys saying that those 147gr loads are for SMG's, due to the higher velocity enabling them to expand..... not seeing it.