Upgrade kernel to version past 4.4 on Core for Raspberry Pi 3

Hi !

In order to use a Raspberry Pi HAT (in particular the Voice HAT from the AIY kit) I need Linux 4.9 or greater.
I know that project is intended to run on Raspbian but I wanted to leverage Ubuntu Core’s multiple abilities and enhanced security features.

Anyway, I tried installing edge image then @ogra’s image from this post and even tried to upgrade the pi2-kernel snap to edge but I could not get a kernel newer than 4.4.0-1077…

Is there any way to upgrade the kernel?
Thanks!