I defeated level 9 Olimar.
So that I won't make any unnecessary threads (thanks for the tip, UndrDog), I would like to bring this up again, since it is a discussion about Samus and Olimar. A lot of times, I see people worry about Olimar, because Samus' z-air seems ineffective against him due to his short size. The thing is, if used properly (I dare not say that all Samus mains do this improperly!), you can actually hit smaller characters. I've hit Pikachu, Kirby, Meta Knight, and Olimar. The thing I want to bring up is my battle between me, a Samus main, and Olimar.
I decided that I'd play against level 9 CPUs just for the heck of it. I like to see how they react. While they aren't the best to fight against, you can learn things about them, such as their use of shielding, spot-dodging, air-dodging, and the like. But, that's beside the point. I ended up fighting against a level 9 Olimar. We were at Yoshi's Melee stage. I thought that I was going to lose, because I don't like Olimar's way of fighting. Toss a Pikmin here and there, and you'll eventually get your damage racked up.
Here is what I did when I fought against Olimar. Keeping in mind the stage, it would seem that Olimar would have an advantage here. He wouldn't have to worry about falling off and trying to tether onto an edge. The problem with him at this stage were the slopes. Those slopes did me wonders, because it allowed me to use z-air multiple times. Eventually, I'd get him high enough in damage that I'd simply have to use a d-tilt, d-smash, or f-smash. So, remember that the stage you are on also makes a difference!