I spent 2 weeks In St Pierre when I was a cmas **. I was then limited to 40m, but still enjoyed the dives (not only wrecks but also walls, canyons and such in the area).
I'm going back there for another two weeks this January.
Now I'll be able to dive on the Roraima, which is reported as on of the most beautiful wreck of the area, at least on air (55m depth), and also on trimix if I can manage that.
Unfortunately, I will have to wait for Tamaya, as I'm only officially qualified to dive to 70m on trimix, whereas Tamaya lies at 85m.
There's also supposed to be a few shallow (30m to 40m) nice wrecks in the south of the island, such at the Nahoon or the Sikorsky (a flying boat sunk in 1945). I haven't been there yet.
Regarding your dive certification, you'd better contact the locals clubs beforehand, to know how you'll be treated (and several of them, as all might not do the same thing). I just don't know, especially for deeper wrecks. It should definitively help you to be effectively TDI qualified, as this agency is part of CMAS, and well recognized.