I've already written volumes about both keyboards, and I respect DanO's opinions, BUT I must agree with Uncle Dave. The Yamaha is so much easier to learn and operate. Also, if you have Clavinova disks, they will work on the PSR9000, not to mention any volume pedals or footswitches you may have left over.
The only downside I can see on the Yamaha is the weight, and that won't matter to you.
I find the speaker system is quite loud enough to practice at home without distortion, but it's not as loud as the X1. The effects are far more versatile.
As for styles, if you buy the Yamaha you won't need to convert them to X1. And there are countless styles available for download on the internet, if you find you need some that aren't there.
If you can, talk to a dealer who can let you try both, then make your decision based on which one you like best. I also know a lot of folks who prefer the Technics KN6000 for your type situation. You can't go wrong with any of them, but if you try them all, one will be a clear standout to you.
Good luck!
P.S. If you decide to buy an X1, Tom Cavanaugh has a used one for sale, complete with hard drive, harmonizer, expanded memory and 6-switch pedal.