It is all in the head I guess. Technically speaking, I think he wasn't any better in 2009 than in 2008, but the fact that Nadal crashed out of the FO and then could not play at Wimbledon paved the way for a boost in confidence.
At the beginning of 2009 Fed was frankly playing like crap. He seemed to have lost all his confidence with the racquet breaking incident against Novak as culminating point. I really wonder what a fresh Nadal would have done to his confidence.
Anyway, Fed is still a helluva player, but he is beatable as Delpo showed. His prime is over, but he is still a major threat on any surface.
"Most of us believe in trying to make other people happy only if they can be happy in ways which we approve." Robert S. Lynd