I've read a few places, even here, that some Nexus 9 owners are getting the newest update already for WiFi versions. Any reason why that isn't happening for all Nexus 9 owners?
Updates are sent out slowly, a few devices at a time, to prevent the internet from crashing. (Try getting somewhere late on April 15, or on Christmas day, and you'll see why.)
Apple does have this issue. There IOS 8 release killed voice and texting for 50,000+ phones before they withdrew it 30 minutes after release. They deployed a fixed version later in the day, but in the meantime it must have been tough for the effected users.