At your level, you're probably not going to be able to beat CM9k. Instead of focusing on openings, I'd suggest just working on general chess principles. Assuming you have a reasonable computer, you will need to get to about 2000+ in real life before you can expect to get a good game against an engine.
At that point, I would suggest playing chess like Kramnik. The Berlin Defense of the Ruy Lopez may hold a draw, and solid chess will be your best bet. I'm not exactly sure how strong this engine is, but I'd expect winning against it a below-GM level is highly unlikely.
Yesterday (1st July 2012) I played a game against CM9k, a very strong chess program. Playing against a program like Chessmaster 9000 is not a walk in the park. CM9k is absolutely merciless punishing errors, is annoyingly patient and has a perfect memory for openings and endgames. Computers almost never blunder tactically, although they can make major strategic errors.
It was this strategic deficiency that I wanted to exploit vs CM9k. I hoped to steer our battles to quiet maneuvering trench warfare that requires judgment and foresight rather than brute calculating ability.
1.e4 c6
This defense prepared before-hand is known as the Caro-Kann Defense - a very solid system that has a reputation for being effective against attacking maniacs and computers. So, is this the best chess opening against a computer? Any help taken