The android version is separate and is only available on the Google Play Store, so yes, it needs to be purchased separately.
There is also a free version which you can try to see if it works on your setup.
https://play.google.com/store/apps/details?id=com.Freeride.Freerider
https://play.google.com/store/apps/details?id=com.Freeride.Freerider_FREE