Well, yes and no.
If the Rohloff has got a quick release, then the official line is that the QR won’t clamp the hub in the frame with enough force to stop it slipping under heavy pedalling loads. therefore, you would need to locate the hub at the very front of the slots, so it can’t get pulled any further forward, and use a tensioner.
I’m guessing that’s what your LBS has done.
Unofficially, I ran a Rohloff in a slot dropout Chameleon and found that not all QRs are equal. Some would hold the wheel solid in the slot, some would let it slip forward, no matter how hard I did them up.
If only I could help you by remembering which were which. 🙄
As a suggestion for now, leave the tensioner on, but move the hub back in the dropouts.
If you find the hub creeps forward, just move it fully to the front and carry on and consider buying a better QR.
If it doesn’t move after several rides including a few steep hills, do away with the tensioner, you don’t need it.