I'll add my experience to this ... Android 9 shows a white screen only (so no map, no controls, completely empty) A beta user reported this and I then purchased a cheap Android 9 phone to test and I get the same. I've not seen any issues on any other versions of Android (I've tried 5.1.1, 6.0, 7.1.2, 8.1).
The app is set to target API 28, but I get the same result with a simple test app using the map component and nothing else and without changing the target API. I'm using Delphi 10.3.1.
I have TMS All Access so for now at least I'm going to replace the map with the OSM one, but a fix would be great.
This might be a clue: I enabled ShowDebugConsole for the map, and that (on Android 9) gives me ""access to restricted url denied" in the script window.
I checked just now. I've misled you ... it actually says "Access to restricted URI denied", not URL. Sorry about that. There's no other information provided.
I have had exactly the same issue - no maps on Android 9.0 - only blank white space
Fortunately I also saw that Exoplayer started to have the same issue which was that it was unable to connect and send a simple http request to its usual URL
I found the solution was to add the usesCleartextTraffic='true" to my manifest and now this has solved the problem