Yes, Linux 4.9 Is A Long-Term Kernel Release
Greg Kroah-Hartman confirmed today Linux 4.9 is his latest LTS branch with this message, "Might as well just mark it as such now, to head off the constant questions. Yes, 4.9 is the next longterm supported kernel version."
Linux 4.9 was a great release and introduced many new features. But if you're a feature-addict like me and not running your systems in a heavily critical environment, Linux 4.10 is where the fun is now at.
Linux 4.9 is the first LTS kernel since Linux 4.4. Linux 4.9 LTS is expected to be maintained until January of 2019. Linux 4.4 is being maintained until February 2018 while the Linux 3.18 LTS kernel maintenance is ending this month and the Linux 4.1 LTS maintenance is ending later this year.