Will watch the video. I'll let you know what I think below. Also, check out the Match-up thread and tell me what you think.
EDIT:
So the first match, I'm seeing you get OCVed by Clark, but this is because of some things you're doing that you're doing in every character. For one, you're not respecting Clark's space. You have King, who could easily zone Clark, but you're running in. With Maxima, you really can't do that because most of your moves wind up not respecting his space.
Another thing, I think the big thing here, his roll setup confused you. He rolled in on you and did his B command grab a lot. He'd roll and do machine gun punch too. What I'd suggest, if you have meter, is to neutral hop. If you feel like you're going to get grabbed, neutral hopping stops him for free. You can even do j.D and smack him for a full combo. He really LEANED into that crap. I know how you feel; I have to deal with it a lot against CharREX. If he stops doing the B grab and goes for a normal combo, you can also wake up and do a command grab. He did not seem sloppy with his rolls, but you can feel it out if he's going to be behind you.
So finally: How to deal with early jump CD
The active frames on the move are long and they're vertical. You're likely not going to beat it air to air. If he's going to try to keep you in, with any character, I'd throw out a move that's in invincible on start-up or something I know will trade. For one, Maxima's st.A is five frames and will likely trade with Clark if you throw it out. It's a great deterrent for hops. If he's jumping really high, but you're certain he's not going to cross-up, I'd throw out a df+C. It costs you nothing, you'll get counter hit, and probably break even. If you think he's going to do it. If you have meter, you can use DP+BD. You could do the regular Double Vapor Cannon. If you're feeling you can time it just right, you can neutral jump and do EX Air Vapor Cannon. High in the air, you'll land way before he does and be able to time an EX Maxima Press for a pretty nice corner combo.
Let me touch on more about the df+C. If he's really jumping high, I wouldn't do it. You'll likely miss. However, if you think he's going to hop and do it, like time it real deep? I'd do it and follow it up with DP+B. Put your dummy in practice mode, as Clark, and hop at Maxima for a meaty CD. As Maxima, do df+C and the dp+B. You'll notice you'll counter hit him. You can follow it up with dp+B. Now he's knocked down. Staying outside his grab range, go for a meaty sweep. You can try to set the dummy to do his B grab or D grab, but what will likely happen is you'll hit him as he wakes up. If he blocks, you scored 233 damage. If he didn't, he's knocked down again and you did 300 damage to 333 damage to him. This is very serious punishment. You want to make him scared of YOUR hop space now.
In the corner, that's a little different. If you try to do something like even punch him, your st.A or st.C might whiff and he'll hit you on the way down. If he times it meaty, doing st.D is great. Why? Even if the move his slow, you have guard point. You can CANCEL guard point at any time and nail him with a regular vapor cannon or a D grab if he's too slow to react on the way down.
If you think he's gonna jump over you and if you press a button he'll cross you up, you can do C vapor cannon the other way (qcf+C). What this does is puts him in the corner and guard points his jump in. Giving you the opportunity to hit him when he lands.