In case you do not know, hotspot does not work on the Sprint variant of Samsung Galaxy Note 9. There is a mod that solves this very problem. The best part is that you do not need to root Note 9 or even install TWRP recovery to make it work.
Just keep in mind that you must reapply this Galaxy Note 9 Sprint hotspot mod everytime you update profile on your device. One way to do this is to disable automatic updates so that the profile updates do not get removed.
1. Download Shortcut Master Lite from the Play Store.
2. Open Dialer
3. Dial ##brand# (##27263#)
4. Say yes/accept everything – phone reboots
5. Open Shortcut Master Lite and select the Menu (three vertical dots in the upper right).
6. Select App Explorer, and then All Apps
7. Navigate (scroll down) to com.test.LTEfunctionality and select.
8. Select the first item labled “LTEFunctionalityTest” and select launch.
9. Scroll down to LTE APN Setting and select.
10. Select APN2 LTE/EHRPD internet
11. Scroll down to APN type and select.
12. Add “DUN” to the setting (it should read “default,mms,DUN”) without quotations. Also make sure there is no space between the comma and DUN.
13. Select Menu and save your settings