From what I was told by the devoper, if you pay for the app you would be able to use it on multiple devices as long as they set up on the same account. So I went ahead and paid for it and the Play Store loaded it on my AM9. When I tried to load it on my ONN Pro the Play Store wanted me to pay for it again.
But to answer your question, I am fairly certain that the app is only good for the account you originally set it up for. Unfortunately, not so in my experience even with the same account.