Full-time nanny

We are a family of 7. Our five children are 4 (5 in August), 9, 11 (12 in October) and are other two are freshman (won’t need childcare but will be home during the times). Our 9 year old and one of the freshman are only here every other week. Pick up 4 year old from pre-k at 11am and every other week pick 9 year old up from school. During summer months bring 9 year old to and from football camp. My husband has random days off during his work week so some weeks would be 40 hrs and some would only be 32.