That's very easy to do in this arena
What are you going to use the end result for ?
Do you know if you will be scanning Kodachrome ?
Here are a couple of reviews of the two mentioned.
http://www.filmscanner.info/en/CanonCanoScan9000F.htmlhttp://www.filmscanner.info/en/EpsonPerfectionV750Pro.htmland from here
http://www.imaging-resource.com/SCAN/CS9000/9000F.HTMThe 9000f looks like a reasonable scanner. It opticaly resolves less than the Epson V700/V750 (1700 ppi vs ~2000 ppi) for film , so that will only be an issue for straight enlargement of 35 mm for printing. The LED based light source should reduce the need to profile the scanner with an IT-8 target for all but Kodachrome (assuming there is not a default profile from Canon).
A film scanner will out perform any of these, but adds cost.
What image editing software do you use ?
BTW, Vuescan is a reasonable scanning utility for most purposes and i would use either it or Silverfast if CanoScan does not meet your needs. The nice thing about Vuescan is that one license is good for any scanner while Silverfast is one license per device.
There are technical issues with all of the scanners, but what is good enough depends on the final use.
You might be able to borrow some time on a scanner at a local community college or friends, if you have never done this before, to get a feel for what you are getting into.