Alekhine Defense: White's repertoire

1. e4 Nf6 2. e5 Nd5 3. d4 d6 4. c4 Nb6 5. exd6 cxd6 6. Nc3 g6 

White will proceed with Be3,Rc1 and b3 while Black is putting his bishop on g7

 7. Be3 Bg7 8. Rc1 O-O 9b3 

Here we are at a crossroads.

Black can play 9..Nc6 which White should reply with 10 d5!

or Black can play directly 9..e7-e5 leading to an ending after 10 de5

Here's the position after 9..e5, where White should take on e5