Curious where you are getting those version numbers. The latest version of Numbers 3 is 3.6.1. The latest version of Numbers 2 (part of iWork '09) is 2.3. There is no such thing as Numbers 9.2 or 9.3.
If you're running Numbers 2 you definitely want to be on 2.3, to avoid crashing problems.
Since Numbers 2 is "orphanware" in the sense that it is over 6 years old and is no longer being developed, there may come a day where it won't work. So it might be a good idea to start easing into Numbers 3. It's matured into a capable app since its early releases, and is about far more than "integration with iOS."
Both versions 2 and 3 are stable on my system. I now tend to update fairly promptly because a lot of updates these days squash bugs and result in a better user experience. That's different from the old days when updates carried much more "early adoption" risk.
SG