The main reason for using CF or Kevlar is strength and only strength. High strength fabrics allow builders to build lighter. The layup can sustain heavy impacts even tho' there are fewer or thinner supporting layers of 'glass. But there is a trade-off. Thinner layups are more flexible and mean ribbing and other stiffeners need to be added.
I've only seen one CF hulled kayak and I think there was Kevlar in the fabric because there were gold flecks in the weave. The boat was very long, very skinney, very light but not anything that the average paddler could handle.
In paddle boats hull shape and finish are probably more important than lightness. If the hull isn't slippery a layer of CF or Kevlar won't help it.
When you want stiffness and light weight think PLYWOOD. Good ol' plywood produces hulls that don't seem to have any "give" in them.
My kayak is a notorious "Yare". It weighs 29 lbs. is 16 ft.long and is only 3mm (one-eigth inch) thick. It's as stiff as an i-beam. It won't survive a ballpean hammer attack but it's as light or lighter than most miracle-fiber hulls and it only cost $300 to build. If I could figure out how to build one with more room for my big feet I'd do it again.
Charlie