If not home schooled, they're most likely going to Central Christian in Kidron or Kingsway Christian which is south of Orrville just off Rt. 30. Kidron is part of the Dalton Local SD. It's unlikely, but any Catholics could make the short drive to St. Barbara's on the west end of Massillon, but there can't be many doing that since St. Barbara is a rather small school.
EDIT: The article finally opened for me. After seeing a few other districts that also have large Amish populations (Cardinal, East Holmes, Garaway, Southeast (Stark, Holmes, Wayne), and West Holmes), I would say Amish home schooling is the driving force behind the numbers in those districts. The numbers plummet in HS because many Amish do not attend school past age 14. Dalton has its share of Amish and Mennonite in its district.