Does anyone have Olimar experience? I need help, because playing against CP9 feels like playing against Fox with a sword, except I can't punish him as hard because he's lighter.
And I'm having trouble with his comboing me with nair-uair or nair-fair
In my opinion, Olimar is Zelda's 2nd best MU (after ICs), mostly because LCN beats 90% of his toolkit. The most important is to prevent him from playing his game. Part of what can make Olimar difficult is when he gets flowered Pikmin...so just don't let him do that! Like any "Power Up" archetype fighting character, he suffers in practice, because he has to wait to be a real character. Kick his ass before he gets a chance to do that.
His DD/WD game is much weaker than Fox's, so much so that yours is almost as good! The disjoint...yeah, that'll give you some issues. His range is surprisingly good for such a tiny character, but that's really all he has going for him against Zelda. That said, outspacing LCN is hard as balls for him, and he tends to have to punish the endlag, like everyone else. His frame data is pretty average, and his best moves have decent startup (including fair and bair, which are the only scary things in neutral). So stay on the offensive and don't give him too much space.
Offensively...Olimar has trouble escaping Zelda's combos, because he's on the floaty mid-weight spectrum, like Marth. Use that to your advantage and get your floaty combos going (f-throw > fair, nair > fair). He also has an absolute GARBAGE techroll, which means that d-throw is a super good option. You should be able to reaction techchase if he DI's properly, and if he DI's in, you can get bair, nair, up-air, or a re-grab. His model size is very circular, which means that hitting sweetspot kicks is on the easy side, because you don't have weird limbs protruding to mess you up.
Edgeguarding...is a piece of cake. Grab ledge, force him to stage. If he wants to sweetspot, he's in perfect position to get hit by a dropzone kick. If he tries to do ANYTHING ELSE, you can up-b gimp or dair him, because his hitboxes on up-b are pitifully small. If you want to play it safe, then make him land and punish the 30 frames of endlag.
Defensively...up-smash OoS obviously doesn't work, but you can up-b > instant cancel > up-smash combo him. Grounded Nayru's is also super good against him, because I don't think he can get throw follow-ups on us, and Shieldgrab is the way that Nayru's is usually punished. I don't know if I was ever hit by nair > something, but I was up-air juggled occasionally. That's just a Zelda problem, though. Make sure you don't burn your jump prematurely, and use **air dodge** or good telecancels to get down. On the off chance that you get hit by side-b, nair or LCN can clear the Pikmin easily.
Don't get caught by dumb stuff...Remember that unlike most tether grabs, his grab is active THE ENTIRE TIME the Pikmin is out. It's active for 14 frames, which is a VERY long time for a grab/hitbox to be active. Reds deal more damage, Yellows have faster frame data and are larger, Blues have a bigger grab and stronger throws, Whites are good for comboing because of lower KB, (and you'll need to use a GTFO IMMEDIATELY if you get hit by one, or you can take as much as 80%) and Purples have stronger KB. Everything can be DI'd out of, and he doesn't have very many DI traps other than his throws (learn those). He can b-reverse and wavebounce with Pikmin Pluck and Whistle to mix up his movement (which Steelguttey is quite good at), but if you keep near him, you should be fine