Florence Giotto Pass - Bell tower

Per the website, you can't use your pass the day before your reserved time to climb the tower, You can, however, use it to visit any of the monuments it covers earlier on the same day of your reserved climb.

https://tickets.duomo.firenze.it/en/store#/en/support/faq

Can I Enter the Monuments Before the Booked Time Slot?
"For all available Passes - Brunelleschi, Giotto, Ghiberti - you must book an access time-slot (which cannot be changed or cancelled) on the first day of validity of the ticket. If your slot for the Dome, the Bell Tower or Santa Reparata is set in the afternoon, you can still enter the OTHER monuments included in the ticket even before the one booked, as long as it is on the day of validity.

For example: I booked a Giotto Pass with a climb to the Bell Tower on April 4th at 12.30 pm, I can enter to the Museum or to the Baptistery before 12.30 pm; I cannot enter any monument on April 3rd. The 3-day validity for all Passes starts from the first day of visit (4, 5, 6 April in the example)."

As of now, there's no way to purchase the Tower Climb separately. How about if you buy your pass and schedule the Tower Climb for the afternoon of Day 2 and then visit the other sites included in the Giotto Pass that morning?