I thought thetsmae thing, but found it. It's a hidden feature. Tap and hold the photo mode on the option scroll wheel and a hidden menu will pop up. Scroll down on this and enable virtual shot. That's it. It will be in your scroll options from now on, unless you disable it
I doubt it's an S9, sounds like an older phone with the mode built in to the Samsung app.
The only way I've ever been able to do 360 photosphere photos is by using the Photosphere mode in a port of the Google Camera.
After the S9 Pie One UI update, I've tested loads of ports by different developers. iDan's port ("GCam_5.1.018.177470874.41362666_IDan_N6_3.5_fix.apk") is the most stable, works with HDR+ without overexposing in daylight and works in portrait mode. I installed his 4.1 build after 3.5 build and it's working fine. No root required. See xda-developers for more info and download links.