Though we're in January 2019, US mobile carriers are still rolling out December 2018 security patch to their devices and now, Verizon is rolling out this security update for Galaxy Note 9. While other carriers such as Sprint, T-Mobile and AT&T's Note 9 are still on November security patch.
This update brings the December 2018 security patch, providing fixes to 40 Samsung Vulnerabilities and Exposures (SVE) items.
The Galaxy Note 9 is receiving this update as build number N960USQU1ARL1. If you want to check this update manually, head into Settings > System updates > Check for system updates or you can simply wait till the update automatically appears on your phone.