Hi Stefan,
I had a feeling it was printed somewhere in Europe but I wasn't sure where - thanks for digging it up!
Yes, 7...f5 is probably the objectively best move if you want a complicated struggle, but this 7...a6!? sideline is also interesting. If you refuse to play 9...Nd4 because it leads to more simplification than the others (a fair criticism for sure) then I agree that I'd prefer 9...Nge7 for the reasons you stated. In all these positions with a likely exchange of dark-squared bishops it's far more sensible to keep it on a circuit that allows an easy relocation to d4 or f4. Here like you said there's g6-f4, or g6-f8-e6-f4, or if you decide to move the c6-knight, there's Ne7-c6-d4 as well.
I can't remember where I mention it and if it's in the excerpt (and I'm too lazy to check), but a lot of times in these early Be2 systems I like to play ...Nd4xe2 before White increases his control over the d4 square with Nc2 (not relevant here) or Be3. Frequently you reach similar positions to those with other moves, except that you've exchanged a pair of minor pieces and grabbed a bishop for little cost. For instance, after
9...Nge7 10.Nb3!? (I don't know if this is best, it's just an example - 10.Nf3 is logical too)
10...Bxc1 11.Rxc1 O-O 12.O-O, Black has some small problems, even though they are most likely solvable. White can meet
12...Ng6 with 13.g3, when perhaps that knight would rather be somewhere else, and
12...Be6 with the simple
13.Qd2, starting to target that weak d6-pawn. All the engines prefer White a smidge, but Black's position seems very playable. All that said I would like Black's position more if that Nc6 was traded off for any of White's minors.
9.Be3!? is interesting indeed, though I'd prefer Black after the obvious
9...Bxe3 10.fxe3 Nf6 (I prefer the knight here now that d4 and f4 are no longer options - c5 seems a likely home)
11.O-O O-O 12.Nd2 and now perhaps
12...Be6 is the easiest. I am reluctant to allow Rxf6 ideas after 12...Qb6.
Perhaps all of our analysis will make it into the second edition! I hesitate to use more space for a third option in an uncommon line in a book that's already nearly 500 pages though.