The Galaxy Note 9 is getting a new software update in the US and Canada. In the US, T-Mobile has released the May 2019 security patch for the device. The international version already received the latest software update.
The update only includes the security patch for the month of May. There’s no information about the camera night mode. But, we could probably see this in the next update.
The T-Mobile has a software version N960USQS1CSE1 and the size is 154.38MB. While the Canadian update brings software version N960WVLU1CSE1 and the size is 537.20MB.
You can check for the update by heading into the Settings > Software updates.