Searching for a "Google Play Store APK download for Android TV 9.0" usually starts because the icon has seemingly vanished or isn't working right. The good news is that the Play Store is a core system app on Android TV 9.0, so you rarely need to download a "new" one—you usually just need to find or fix the one you already have.
Or go directly to the official page (search term): Google Play Store for Android TV APK Google Play Store Apk Download For Android Tv 9.0 Free