Fooshman is correct please don't think you are where a normal boat can't go. In my Stumpjumper, if I hammer down, I draw less water and I can run wide open 26 to 30mph in about 8" of water. If I stop I am there to stay.
I agree that kayakers, canoers and power boaters all need to be careful. Kayakers always need to keep an eye
and ear peeled for boats and need to stay out of boating lanes as much as possible. However, going 30MPH in 8" of water is not a "normal boat" and is inherently dangerous. If you are running that fast in 8" of water or within 20 to 30 feet of any bank, you have the greater burden to watch out for other boats, waders, swimmers, deer, rocks, trees and anything else that may be in shallow water.
It sounds like the existence of a kayak had little bearing on what happened to the OP. It sounds like the same would have happened if it was a jon boat or dark-colored bass boat. The OP simply let his guard down and was messing with a dog while running wide open. If we are driving down a country road all lone with a dog on our lap... do we have less of a duty to watch for other vehicles, motorcycles, joggers, bikers, etc? Nope.
Im not throwing stones at powerboaters nor am I defending kayakers. Until very recently, I've owned a power boat my entire adult life. I love the water and consider myself to be a very safe operator. However, a few times over the years I have accidentally ran too close to other boats... each time it was my fault. They were minding their own business fishing and I ran into a cove or around a point too hot. I didn't do it on purpose (nor did the OP) but it was my fault. Period.
I greatly appreciate the OP reaching out to say sorry and I think this dialog is very helpful. We all need to watch out for each other. When PB's operate in shallow water, near the bank or around a blind bend, they need to go slow. At the same time, kayakers need to be mindful that we are hard to see and need to make ourselves as visible as possible. We all have the burden to watch out for each other.
Safe boating!