Yes it worked for me. I have Chromecast and was was able to cast my N9 screen to the TV. My N9 screen was mirrored.
Build number: LRX21L (system says I am up to date)
As to how good it was that's a whole different topic.
4:3 cast to 16:9 TV not worth the bother in my opinion. Black bars on either side of the mirrored image on the TV.
Add YouTube video to that and you have black bars side and top.
Game projected did not fill my TV screen had black bars on either side.
Real Racing 3 Game lagged/stuttered when displaying on TV
YouTube not much better.
Tried streaming a video from the PC video stuttered and audio was out of synch
Am I missing something in my settings?