Here's what I'm thinking (doing classic of course)

m,w,f being the lifting days

t, th, sat being the cardio days. Alternating each time between plyo and kenpo (so in other words weeks 1 would be plyo twice, kenpo once. Week two would be kenpo twice and plyo once. And on and on)

Yoga x done on sundays.

I just like the thought more of having that extra day of cardio. 3 days cardio, 3 days lfting, 1 day yoga sounds perfect to me

You need a rest day.

Better idea would be to add a Cardio X workout on one of your resistance days, as in the Doubles schedule.

Even better (imo) would be to add a short HIIT routine after one of the resistance workouts.

Program works as is, Leave it alone

I agree with Pauly.

Your body needs recovery time and the weeks you are thinking of doing Plyo twice which is a leg workout you are also doing Legs and Back in there. This is too much for this one body part you need recovery time.

My two cents.

I don't know if you have seen the Yoga X video and I don't know your level of fitness. Yoga X puts a lot of stress on your chest muscles, depending on your fitness levels of course.

I would say o just do it like it was designed for the first Round (full 90 days) and then you can change it up when you become a graduate.

If it's not broke, don't fix it. The program works as it is, don't tweak it or fool around with it like you're planning on. You're setting up for injury.