Yes, this is covered within the license for personal use. Simply log into your second device with the apple ID (email address and password) that you’re using with the first device, then go to the app store app, tap on “Purchased”, and all your apps will be there. Tap on the cloud icon next to the apps you want to download. You will not be recharged.
Please note that Predictable for iOS and Predictable for Android are separate pieces of software requiring separate licenses.