Yes the IP is in scope - but the firewall gui which should never be available on that IP should not be… You turn on pfsense out of the box there is NOTHING open on the wan, ZERO services available - shoot it does not even answer a ping.
Any traffic you allow inbound would be involved in the scan,not services that would never be available on that public IP..
You creating a firewall that allows access to the gui from the wan is what would put it in scope - why would you do that... There is ZERO anything pci compliance that would suggest you would open up a devices admin gui to the public internet..
A pentest against this IP would be in scope... They can pentest all day - but you opening up the web gui to the public should of never happened. If they can access the webgui via a pentest when you have not allowed it then that would be in scope - and would be a whole shitcan of worms.. But you creating a specific firewall rule that allows access to the gui or any any to the wan IP is just not correct way to do this sort of scan or any sort of pentest or compliance test at all.
Like saying hey we want to test the lock of your door.. Unlock it please - oh yeah that lock doesn't do shit, it opened right up...
A pentest or compliance test is against service that would be open or finding stuff that is open and should not be.
auditor: Hey you have ntp open on port 123
user: Yeah we need that
auditor: Ok it must meet xyz if your going to have it open.
user: Ok we will do xyz
auditor: Ok scanning, yup its version X, it doesn't allow that or this - your good
user: thanks.
auditor: Hey you have ntp open on port 123
user: Oh shit really - we don't need that. Closed
audiotr: Ok let me check - yup no ntp anymore your good.