Well, I would highly doubt it would be on the Ronkonkoma Branch now that it is back to single-track service for Central Islip, Brentwood, and Deer Park. It wouldn't be from Huntington because of the Third Track Project (this also affects Ronkonkoma Branch service). The last time we had a maiden voyage in which the lead car's number started with a 9 was on December 30th, 1968 with the M1 from Babylon to Penn Station, and the maiden M7 was from Long Beach to Penn Station on October 30th, 2002. I wish I was hoping it would be the Ronkonkoma, and who knows it probably could still be, but the branch is having rail-tie replacement of Track 1 currently from just east of Central Islip (where the new track connects to Track 1) to JS, then as soon as that's done the work moves to JS to where BRENT was located (where the new track is connected to Track 2). The Babylon Branch was undergoing elevation, but had two continuous servicable tracks.
This is the train to (NYC). Stopping at: Babylon, Lindenhurst, Copiague, Amityville, Massapequa Park, Massapequa, Seaford, Wantagh, Bellmore, Merrick, Freeport, Baldwin, Rockville Centre, Lynbrook, Valley Stream, Jamaica, Kew Gardens, Forest Hills, Woodside, Penn Station OR Grand Central.