Scandinavian Defense
Overall, nice positional game. I do get the feeling that 9...Nb6 is not good, as it is a completely unprovoked retreat and as you said allows moves like Bf4. Only against Be3 did the knight b6 have prospects, as against say Bf4, ...Nc4 wouldn't be very useful after b2 is defended, meanwhile more time is wasted. Something can be said for preventing tactics sometimes but here you must be just seeing ghosts as the d5 knight was in no real tactical danger at all, so taking a full tempo to actually make a piece worse will probably give your opponent new opportunities. I would here just wait until white increased the pressure on d5 or weakened himself with c4 and try to keep my development going.