Android is android regardless of maker

Root (your p9 should have a root for it check XDA )

After that downgrade your firmware to a version before march 2017. I would suggest around January 2016 is the best that's worked on multiple phones for me .

then get a GPS app , decompile it , change some key values like its name, maybe remove the ads and payed restrictions , resign and compile it , install it as a system app .

remove root, check if you pass safety net , happy spoofing .

it sounds like allot of work and it is , kinda . it takes work and your gonna have to read through tutorials, take a weekend and pull an all niter to do it as there is no one easy way , even then the app you chose or your phone itself could do something unexpected . what works on one phone might not a other .