I currently have 9 gigs of 1066 ddr3 and was going to upgrade to 6 gigs of 1333 for O'Cing. Would this be worth it in the long run and i have a alienware computer which dell set up the O'Cing from 2.66 i7 to 3.2 but it does not allow without 1333 ram.
If you are gaming, the RAM speed it's self will not make a lot of difference.
However, if using the faster RAM will allow you to overclock your processor from 2.6 to 3.2 ghz, that is a big difference, and you will notice quite a jump in performance.
Now, for the amount of RAM, 9 gig down to 6 gig, no worries. Unless you are doing something completely off the wall, 6 gig is plenty of memory.