In the past 2 years the average screensize of smartphones has broken the 5 - inch barrier on even lower - end models, making them far more suitable for casual ereading on the go. (goodereader.com)
This is one of the downsides of Android in general, there are so many different screensizes and resolution that it makes it impossible to push out HD content properly. (goodereader.com)
And of course «Nexus 9» also lines up with Google's traditional «Nexus [screensize]» naming scheme for tablets. (gizmodo.com)