The kids mode was there available as a standalone app since the Galaxy S5. On S5 it was pre-installed, on others it can be downloaded from the Samsung Market.
Some Note 9 users including me has camera issue.. the camera module vibrates when trying to zoom 1.5x or higher both in photo and video mode and also on live focus mode.. this results into a blurry image and video footage. Please make a video ragarding this matter as i have not yet seen any Popular RU-vidr discussing it. Thanks in advance