I't barely dx9.
The default PS is 1.1 (hardly dx9 material), it's written in CG, and any CG capable hardware uses that as the rendering path. Any other card uses the none optimized path. Just so you know, Nvidia's official statement is that this game is what they accept as a gaming benchmark, as well as a dx9 benchmark. Curious that this game has less dx9 features in it than 3dmark03. If this were a complete dx9 game/benchmark, a Gforce Ti 4600 wouldn't be able to run it. Seems to me that since it is capable of running it, that this is (by Nvidia's own definition) not a true dx9 benchmark.
Feel free to argue this point with me, I'll just quote Nvidia's own press releases to back me up.
Not all chemicals are bad. Without chemicals such as hydrogen and oxygen, for example, there would be no way to make water, a vital ingredient in beer. (Dave Barry)