If it's a Shimano-compatible cassette, and you have a Shimano-equipped bike, it'll fit and work just fine.
When 9-speed was the new thing, all the ads touted "reduced cog spacing," meaning you could upgrade
your 8-speed bike with new deraillers, shifters, and cassette, but you could keep your existing rear wheel.
No innovation is painless, though... since there's less space between cogs, 9-speed bikes have to run a narrower chain that 6-7-8 speed.
I'd imagine that all you're trying to do is replace a worn-out 9-speed cassette without taking out a second mortgage to buy Ultegra or Dura-Ace, and you're wanting to try a Performance or Nashbar brand cassette.
It's a little heavier than the "good stuff," but it'll work as advertised. I've had a cheapo Performance one on
my 1999 Specialized Crossroads going on 20K miles now, and it still has all its teeth...
Go for it.