Route 9 started operating in 1974 as a replacement for other various lines that served Baltimore's York Road corridor north of Towson; historically, all portions of York Road Towson and southward were served by the no.
Route 9 began operations in 1974 as a substitute for other lines that served Baltimore's York Road corridor north of Towson; historically, all sections of York Road from Towson to the south were previously covered by the aforementioned route.