I have a question regarding the line 1. e4 e5 2. f4 exf4 3. Nf3 d6 4. d4 g5 5. h4 g4 6.Ng1 f5
After 7.Nc3 Nf6 8.Bxf4 fxe4 and now 9.d5 is meant to give white a good game.
In a recent game my opponent stopped those plans by playing instead 7.Nc3 fxe4 8.Bxf4 d5
8..d5 is given a question mark by Bangiev in Das angenommene Königsgambit, which is the only source I have where this move is mentioned. The game Jensen, S. - Wölfelschneider, P.,  IECG, 2002, followed the Bangiev line of 9.Be5 Nf6 10.Nxd5 Qxd5 11.Bxf6 but now instead of Bangiev's 11...Rg8 12.Ne2, Wölfelschneider played the much stronger 11...Bb4+ 12.c3 0-0, and Black is better.

Is my assessment that black is better correct (I certainly could not find a good plan), or are there known cures for 8..d5?

Greetings, Sören Jensen