How to determine if my phone supports AndroidOne?
This article states that:


  Android One is a Google-devised programme for hardware manufacturers making smartphones. Being part of Android One - and labelled as such on the rear of the phone - brings with it a guarantee that it's a solid and stable version of Android that's not loaded with other apps, services and bloatware.
  Essentially, it's a stock Android experience.


Your device is an Android One as shown here, here and here.


  With Android One, your device will receive up to two years of upgrades to the latest version of Android. 


In North America, it was released with Android 7.1. It came already installed with Android 8 in some parts of the world of the world and is upgradable to Android 9.


  Is there a setting I can check that would clearly tell me whether my phone supports androidone or not?


There is no such setting.