Samsung Level U Headphones
Samsung's Galaxy Note 9 still has a 3.5mm headphone jack, unlike some devices, so you can use any headphones you want with it. That said, my favorite lately are the Samsung Level U headphones.
These wrap around your neck, fit great, offer good sound, and have 9-12 hour battery life. I actually own 3-pairs of Level U, in case they ever stop selling them. These are some of my favorite Bluetooth headphones and work great with the Galaxy Note 9 and all its sound controls in settings.