Essential Phone is the only non-Google handset updated to Android 9 Pie today

Google today released Android 9 Pie, the very latest version of the world's most popular smartphone OS. While Google said that only its Pixel devices can be updated to Android 9 Pie immediately, there's actually one more handset that's receiving the update starting today - the Essential Phone (originally launched back in August 2017 with Android 7 Nougat on board).
Some of the novelties that Android 9 Pie brings include a "simpler and more approachable" user interface, Adaptive Battery, improved notifications system, enhanced privacy, and native support for notches.
source: Essential