Attention! If the device was introduced to a google account after the reset to factory settings via recovery menu, your phone will require her to enter for activation.
To reset on a Samsung Galaxy S9 you must get into the recovery menu and perform wipe. This is done by the following algorithm:
Turn off the phone. If it's locked and off, press and hold the button "Volume -" and "Power" for 8-9 seconds.
Then simultaneously press and hold both "Volume +" and "Power"
After 5 seconds release "Power" button. The button "Volume +" hold until recovery menu (5-10 seconds)
Buttons "Volume +" and "Volume -" to select "wipe data/factory reset" and confirm your selection by "Power" button
Then select "Yes" and confirm your selection by "Power" button
