The Huawei P9 Lite is a mid-range smartphone released in 2016 that features the HiSilicon Kirin 650 SoC, and as such has not seen as much development effort as some other comparable devices using Qualcomm Snapdragon SoCs. This disparity is mostly attributed to a delay by Huawei in releasing their kernel sources, but nevertheless since the Nougat kernel source has been available developers have been hard at work bringing AOSP-based ROMs to the Huawei P9 Lite. Thus, thanks to the efforts of Team OpenKirin, LineageOS 14.1 based on Android 7.1.2 Nougat is now available for the device.
The ROM is by no means perfect at this point in time. The developers note that there are issues with the camera and dual SIM, for starters. Still, most features work, so if you're looking for something new to spice up your P9 Lite experience, then check out LineageOS 14.1 at the link below.