How we can assign a work schedule mid way in the cycle?

Can anyone explain how we can assign a work schedule which has a 9 day shift pattern to workers starting mid way in the cycle (not the first day of the cycle)?

We have a 9 day shift pattern of 3-3-3 consisting of 3 day shifts, 3 night shifts, and 3 days off. We have 3 crews on this pattern overlapping by 3 days ensuring that we always have one crew on day shift, one on night shift, and one off. How can I "onboard" a worker mid way, for example on the second day of night shift? Do I need to make 9 versions of the work schedule (one starting on each day of the cycle)? Or is there another way of doing the assignment to start mid cycle?