Try updating all your apps thru the Play Store. I hold off on some if the update has bad reviews and I think that held up my 5.6 update. I got the notice last night but the 5.6 download would not start. After a bunch of apps updated overnight and some more this AM, suddenly the 5.6 download started and I was able to install. Noticeably faster and smoother.
16g stock, 1st generation,WiFi only N9