Yes, LTO-9 support will be coming bundled into a future version of ONTAP, and into the ONTAP TCF for older versions in the near future.
If you have an immediate requirement for support of an LTO-9 drive at this time, please lodge a support case, referencing BURT 1466580 and asking for an updated TCF supporting that drive.
If you have no luck with that, please let me know the case number and I will follow up.