I not sure about that ,, I'd check how many devices that Vpn allows ,, is some allow only one and your mobile etc grab it ..
You need look at setting up Vpn on firestick I do believe there's an app for the non voice version
VPN don't work on first generation firesticks only the ones with alexaIPVANISH VPN is for firestick. App from goo#le play. Have not used it but they have a good following.