Replacing d3d9.dll

[CT001]

I apologize in advance if this had been answered elsewhere, I read every sticky and thread I could find on the subject (including the 21 page one on the govenor and Cyphor bitching out everyone, partially why I post this with such extreme trepidation), but being a nub I still may have missed it. Despite having programmed for a while I'm quite new to the whole hacking end of things.

I'm looking to replace d3d9.dll with a custom one. Now am I right in assuming that warden doesn't scan dll's but only scan.dll? Would d3d9.dll be one it would scan?

Would it really be as simple as just adding the custom d3d9.dll to the WoW directory? Or are there other things I would need to do/consider?

Thank-you for your time : )