Ok I tried today - and wanted to give an update.
Overall I think the Scratch X did a very fine job. First of all I tried on an old car I have to make sure that it really does not break the clear coat or anything in general and I can confirm.
Then I cleaned up the specific area real good with water and made sure once again that by getting the area wet, the scratch would disappear.
I did not feel confident enough to use the drill with the pad (it was included in the box) to be honest, so I went with the microfiber cloth and this is the final result.
Yes, the scratch is still visible if you get on the correct angle, but overall it's almost invisible. Wondering if using the pad with the drill would make things even better!