Apps On Multiple Devices
As long as both your devices are registered to the same App Store account at either the Apple App Store or Google Play, you should have multiple copies of the app to use on devices you own. Each purchase is good for the current season only. If you purchased the app last year/season, then restore purchases will not work as each purchase is only good for one year/season.
However, if you have an iOS tablet and an Android phone or vice versa, you'll have to purchase the app again because iOS and Android OS are not compatible.