In this case, the B♭ is the 9th, even though it looks like it should be called the 2nd. Tensions get bumped up an octave (2nd becomes 9th, 4th becomes 11th, and 6 becomes 13th).
Getting a space prepped for a recording session takes a considerable amount of time. If you’re recording clients, or guest musicians, or just helping out a friend, always try to ask for a specific tech plot in advance so you can plan accordingly. There’s nothing that will suck the inspiration and energy right out of the room more than waiting around to set up mics and inputs when the musicians are already done setting up their gear.