Samsung ambassador Gary can help, as he has a note 9.
But I can suggest one thing even though I only have the s9+, try the wearable app. I believe it connects through that app
I can not get my spen to connect to my phone I bought it from Samsung what is going on has anyone experienced this problem how did you fix it
Try taking your old one and place it kinda far away then insert the new one and go to settings scroll down to advanced features and select s pen then select spen remote then click the 3 dots in the top right corner and select reset spen give that a try @userZC8HIxmPhg
Insert the new S Pen into your Note9. Then go to Settings.
Now choose Advanced Features. Select S Pen, and then choose S-Pen remote. Click more options and select the "Reset S Pen"