Back at the end of January, Google released the first preview build of Android 7.1.2 Nougat. It was originally offered for the Nexus 5X, Nexus Player, Pixel, Pixel XL, and Pixel C, with the Nexus 6P promised for later.
Today, the update is available. At the current time, there's only an OTA update for devices that are enrolled in the Android Beta Program, as factory images aren't yet available. It should come in at about 1.29GB.
One new feature that you should end up with is fingerprint gestures. It was included in the update for the Nexus 5X, so it stands to reason that it would be available for the 6P as well. This is a maintenance update, so don't expect any other front-facing features.
If you're hoping to see the update - or any future Android updates - for the Nexus 6 or 9, you're out of luck. Android 7.1.2 Nougat marks the official end of Android support for those devices, but you'll continue to get security updates for the time being.
Google says that the new version of its mobile OS will be available within a couple months of when the first beta release, so it shouldn't be too much longer. If you can't wait, you can sign up for the Android Beta Program here.
Source: Android Police