Okay... we are different pages here.
T refers to the engine management system of a Saab, specifically Trionic. Trionic 5 (T5), is what my 900 is. This can be found on 1994-1998 Saab 900, and the 1999 Saab 9-3 (non-Viggen). T7 is found on 00-02 9-3's, and Viggens, as well as some 9-5's.
So a T9 900 is, not likely. Assuming your engine is stock, it is the B204 (possibly B234, but then it would not be Trionic, it would be Montronic, like my N/A Saab.) You could also have a B202... which is the 2.0L N/A engine. If your engine was swapped to lets say a T7 car, it would have engine code B205 (2.0L turbo from 00-02), or a B235 (Viggen Engine). I have NEVER heard of someone using a T9 engine management system on any of these engines listed, as it would prove ineffective and a complete waste of money. An engine using T9 management, from a newer 9-3, would not be a direct bolt up, and would also be a big waste of time and money.
I have never heard of the Hirsch designation system T9 man talks about, perhaps it is like a Stage thing.