I was just there a month ago for the first time. Kayaking was not on the agenda for me, but I think WW kayaking is slim. I would bet that there are a couple rivers you could actually kayak down, but it would involve hiking your boat the entire length and requiring a big rain. This would be an odd activity on Maui.
So my thought would be don't even bother, but if you do figure out a place to rent a boat and a place to use it, it would be cool to hear about it. Surfing waves in the ocean would probably be your best bet if it's possible to procure a WW boat (again not sure you can rent them) but where there's good surf there are all kinds of weird surfing protocols that I don't understand and locals are territorial around there so you better know what you're doing.
My take would be that you're much better off doing more natural Maui things like surfing on a surf board (good beginner breaks in Maui), or taking out a SUP or windsurfing or hiking to waterfalls.
In terms of paddling around in an ocean kayak, I didn't get a chance to do it in Maui, but the Maui Revealed guidebook (which is THE guidebook) had some little trip they recommended to what they call the "unnamed beach" that sounded cool. But maybe a guru here has some real expertise on the subject. It also seems you always get stuck with the sit on top ocean kayaks when you rent. A real ocean kayak sure looks like a lot more fun.