Watch for tactics or you'll pay the price

I played my weekly league4545 game tonight and my opponent castled short 9. ... 0-0. Can he really do that? 

White to play!

 
It didn't take me long to find 10.Ng5! +- which threatens mate on h7 and Bxb7 winning the exchange. 
Watch for simple tactics, it will save you from losing games. 10. ...Bxg5 11.Bxb7 Bxc1 12.Raxc1 Nc6 13. Bxa8 Qxa8 14.e4 +-