Do not download Zlink APK from random APK mirror sites. Instead, contact your car radio seller (Eonon, Seicane, etc.) and ask for their official "Android 9 APK package." If you already have Zlink on your head unit but it doesn't work with your new Android 9 phone, try uninstalling updates on your phone's Android Auto app (revert to the factory version) before reinstalling the head unit's Zlink.