There is nothing about Linksys routers and 10.4.9 or 10.4.10. There are some AirPort updates that DO impact functionality for SOME people in SOME situations. If you're fine with your AirPort performance, don't install the updates. Really, go all the way to 10.4.10 and ignore the AirPort updates and you should be fine. And if you are going wired to the router, there's nothing at all to worry about.
But you didn't mention if you had a MacBook or iBook-which might help us figure out the kernel panic thing you're talking about.