Eh, what's the use of a single-action 9mm that you can't carry safely in any condition but unchambered? You take it to the range, and it goes "pop pop pop", standard-pressure loads only. Woo. If you want a relic 9mm, I'd get a Star.
The whole enjoyment factor of a TT-33 is taking it to the range with 7.62x25, and the massive fireblast and BLAM BLAM BLAM! that causes people to come out of other stalls to see what the hell you're shooting.
For practical purposes, since it'll defeat anything short of Level III armor and has ballistics closer to a rifle bullet (30 caliber bullet at nearly 1600fps!), it's a good thing to have around, period.
In reply to the poster asking about the Norinco, some of the CommieClone (tm) Toks used to come in a box set with both 7.62x25 and 9mm barrels and magazines, so it should be possible. Good luck finding the parts, though. I don't think any new Norinco-made parts for those can be imported.
It also seems to be an ongoing debate as to whether the Norinco copies are made of a "softer" steel than the original Russian and Polish Toks, particularly that of the slide. I have no idea on that one.