I assume your son took Latin 1 in 8th grade - does this appear on his transcript? Both of the schools I’ve spoken with that want 4 years of foreign language have confirmed that 8th through 11th, levels 1-4, meet what they are looking for.
I’ve never heard anyone say that what year you take a class makes a difference. Skipping a year and then picking it up again makes no sense to me.
Where does UVA say they recommend 5 years of a language? That would be a first. A Google search turns up nothing but “someone told me they heard…”. The documented requirement I find is 2 years.
This sounds like it falls into the “most kids finish Calc BC as Juniors and have at least 2 AP sciences to get in” drivel that pervades CC sometimes.