I already did search - I identified the 9x21 as 9mm IMI (the Isreali round) in my post.
Does the Rhino fire 9mm IMI and 9mm Parabellum?
It may be that the rumor of a Rhino chambering 9mm - meant 9mm IMI
- not 9mm parabellum.
Maybe they'll have something about it at SHOT show. (only 1 more day