In your old account, go to Settings -> Account -> Data sync code -> Generate sync code to share data with another device -> copy the code.
On your destination device, go to Settings -> Account -> Data sync code -> Use sync code to access another account’s data -> enter the code -> Enter. Then the purchase and progress will be sync to another device. Note that, the account is shared between the old device and the new device. You can only play on either device at the same time.