I'd definitely want the advantage of two additional rounds, compared to major, for Single Stack use.
It doesn't seem to be competitive. If you look at results for major matches nobody is winning shooting minor. Rarely a stage may be set up that would really favor 10 rounds but it doesn't happen that often.
The rules also require that a stage doesn't mandate more than 8 rounds from one position, so you generally have time to reload.
I shoot a lot of USPSA single stack and plan on playing around a little with a 9 soon, but I don't think it will be competitive.