That and just staying in front of your man.... I like hearing about the different perspectives with these reviews/roundtables but I've honestly never had a problem with playing defense in 2k9. I control the man guarding the ball handler most of the time or switch between positions and rotate my man over manually. It is somewhat hard at first but once you get the muscle memory it should become second nature switching between 2-3 players in a few seconds to positions them in the correct area with your opponent driving the lane.
Maybe that's too hard for some people (it was for me at first) but since you technically can stop drives into the lane or people just going in for layups/dunks I don't see how it's a problem. Anyone who cares to learn can easily do so.
Now playing online via team up should be even easier because as long as you have a team set up that knows how to player b-ball (that's what my crew seems to be for) you don't even have to worry about switching between numerous players to play D seeing as how your user controlled teammates can do it for you.
I thought being able to switch between multiple defenders and position them before the cut man can make it to the rim was something that was common place amongst b-ball gamers, seeing as how the AI doesn't rotate correctly for you I thought this was a work a round that people used regularly, but I guess I was wrong.