Assume that you are following
http://anholt.livejournal.com/ this is all future discussion. 4.9 kernel is released now. Mainline will move to 4.10 soon. There is obviously a process in which submissions for features are handled ahead of kernel releases.
As for building kernel, if you google, you will find many pages giving you a step by step process to build a kernel. There are several threads around here outlining remastering the kernel into tinycore. Remastering is covered in the wiki too.
Not a simple feat if you haven't done kernel work before.