Kernel is also the #1 app in my list. However, I have not noticed any unusual drain or general battery concerns so far. I will pay attention if the kernel stays on top of my list even when I'm using other apps more heavily.
Kernel wakelocks go through the kernel but they aren't caused by the kernel. Those are system wakelocks. They can usually be blocked if you are rooted and using a custom kernel but the kernel isn't creating those wakelocks or draining power.
