Yes and no. If you run a higher resolution (or lower) you'll get a different score. It doesn't "hurt" your score, it just makes it different. By default, almost everyone runs the bench at 1024x768 and everything on default for comparison purposes. No FSAA or Anistropic filtering.
9550 3DMarks is very good. I score just around 12,000 w/ my dual 7800 GTX overclocked setup. Right now my processor is holding me back from a score in the 15,000's.