This doesn't really bug me too often, but every now and then when I go to text the VKB pops up then disappears, then after a few seconds reappears and then I can type. Also happens sometimes when the security code screen pops up and I have to type the code so I think they are related. It has never been permanent but I still need to wait and very rare it goes away sometimes 15 to 20 seconds before it comes back. Happens to me maybe 10 times a month. Any input would be appreciated as to what I can do to help alleviate the issue. I never installed any keyboard hacks and don't have faster N9 installed if it helps any. Thanks all.

Maybe that's the problem right there

It's almost miraculous how FasterN9 kills lag, so maybe installing it will solve your keyboard problem. I'd recommend version 1.1.4, not the latest version, 1.1.5, because some users, myself included, have been having a few issues with that one. But 1.1.4 is a charm

Does that version fix the stuttering problem when listening to music player?

No problems whatsoever with the music player. I don't know about streaming, though. You might want to check the FasterN9 thread for that.