Yes, trains turned up the Worcester Branch to Clinton and used the lower level there. That connection at Clinton Junction was added in 1903 with the Wachusett Reservoir reroute. Marlborough service was added in 1902 with the addition of a connecting track at Gleason Junction. Prior to that, Hudson was the outer limit of commuter service; the sparsely populated areas west of Clinton never had viable commuter schedules.
Boston's Commuter Rail: The First 150 Years lists 14 weekday inbound trains in June 1906: 4 from Northampton, 1 from Lancaster, 2 from Clinton, 5 from Marlborough, and 2 Wayland short turns.
1917 timetable has 3 from Northampton, 2 from Lancaster, 1 from Clinton, and 2 from Marlboro. One Clinton and one Marlborough, and marginally one Lancaster (9:11am arrival) were suitable for commuting.
1929 timetable has 1 Northampton, 3 Lancaster, 1 Clinton, 2 Marlboro. Same commuting viability.
All passenger service west of Clinton ended on April 23, 1932.
1946 timetable has 3 Clinton and 1 Lancaster, all AM inbound/PM outbound.
Lancaster service ended in the early 1950s. By
1957 there were two Clinton and two Hudson trains. Cuts on May 18, 1958 ended the two Clinton trains, leaving just two Hudson trips. Oddly, those two were rerouted over the Marlborough Branch from Gleason Junction to Hudson.
One round trip was cut on June 14, 1959. It was trimmed back to South Sudbury on January 18, 1965, and cut entirely on November 26, 1971 after a brief increase to 4 daily round trips.