ARCore 1.1 is released couple weeks ago. It has a much broader supported device list but the Google Play Store is still not allowing Nexus 6p (and possible other supported devices) to download and install the tool required for ARCore to run.
But there’s a simple solution, and the best part is no custom-built software is required.
You can simply go to https://github.com/google-ar/arcore-android-sdk/releases to download the latest 1.1 apk file, install it on your device and that’s it!
I can’t say for other devices but it runs perfect on my Nexus 6P.