Hopefully Android 8 will go with 4.9, too, as it hasn't changed its kernel since 3.10

https://www.reddit.com/r/linux/comments/4xf19q/linux_49_next_lts_kernel/

Hopefully Android 8 will go with 4.9, too, as it hasn't changed its kernel since 3.10.

The Kernel version Android uses is not influenced by Google. It is the soc manufacturer that sets the version.