Google recently released factory images for Nexus 4, Nexus 7 (2013) and Necus 7 (2013) LTE. Now it looks like the Nexus 7 (2013) and Nexus 9 will soon get Android 5.1.1.
In a Reddit post Google has confirmed that the Nexus 7 (2013) and Nexus 9 will get the Lollipop 5.1.1 update. The build number for these two devices have been highlighted in bold in the Reddit post. The build number for Nexus 7 (2013) is LMY47W and that for the Nexus 9 is LMY47S. At present Nexus 9 runs on Android 5.0.1 and it looks like it will go directly to 5.1.1. It is not known when Google will actually release the update for these two devices.