Zach makes some good points. The difference in distance I can cast a 8' compared to a 9' 3 wt is negligable. However considering the structure of the brush may be low a 9' rod may keep your backcast above the foilage better than a shorter rod.
If I were in your position and needed a 3 wt I would buy the rod.
If indeed a 3 wt is for little fish (a subject for another thread)the added lever given to the little fish sure makes catching um on a longer rod exciting.