I remember that playing d5 without a knight on c6 gaining a tempo is not the best solution - its probably better to keep the tension and play Be3 instead.

After your 7.O-O e5 8.d5 Nc5 9.Nd2 you get a position of the Petrosian system where black has bypassed some critical lines with Bg5 - the "normal" move order would have been: 6.Be2 e5 7.d5 Nbd7 and now 8.Bg5 h6 9.Bh4 g5 10.Bg3 Nh5 11.h4 looks very committing for Black. Therefore Black usually plays 7...a5 leading to the main line Petrosian system.

Playing Bd7 holds back whites queenside expansion as shown in your game, cause in the end Black plays Na4 equalizing. Have a look at games in the Nd2-line: 1.d4 Nf6 2.c4 g6 3.Nc3 Bg7 4.e4 d6 5.Nf3 O-O 6.Be2 e5 7.O-O Nc6 8.d5 Ne7 9.Nd2 a5 10.a3 Bd7