The sensor on the note 8 isn't actually next to the camera despite every moron reviewer in the world acting like it is. It is next to the heart rate monitor and light. The camera is on the other side of those things.
I had that phone for a year and never once accidently put my finger on the camera when trying to use the fingerprint scanner. That is such an absurd criticism.
Maybe it is too high on the device to effectively reach for some people, I won't say that's an inaccurate complaint, but anyone who has a problem accidently touching the camera when trying to touch the finger print sensor is....well I'll be charitable and say that basically anyone could quickly learn to do it right even if they got the location wrong the first couple tries.
I think the placement now increases the risk of touching the camera compared to the 8. I like to use it to pull down my notifications, but if I put my finger too high to start the swipe down, I'll hit the camera. I'll probably learn to avoid that, but that wasn't a problem on the 8.
For me, the sensor position of the Note9 compared to the Note8 is much better. I just slide my finger up the middle back of the phone and hit it. The Note8 took a few tries most times to get my finger in the right spot. The success rate is greatly improved as well.