Hi, it worked for me with odin and
easy installer did not work for me. It seams (I made no deep analysis though) that the phone could not download TWRP. With odin it worked just fine. I recomend to install samsung drivers manually and not just assume that everything will work out of the box if windows installs the drivers automatically. Maybe this also was a problem for me.
In any case look for instllation guides with odin for the S9 as I can not tell if maybe there is a difference compared to the S7 and the steps to take.
Fingers crossed it will work for you.