OP — I’ve learned Macintosh is usually right about shotguns.Looks like an 1893 no.3. Near as I can see the model 9 (1893 no.9) has some sort of a latch on the left side of the action I’m guessing for the removable hinge pin, and it doesnt have the rounded scallop on the sides of the action.
The buttplate monogram looks like “RA” to me (remington arms?).
Post # 6 on this thread seems to have some very good info. https://www.shotgunworld.com/threads/remington-model-9.469029/
just guessing based on the serial# range and the dates of production 1905 probably isnt too far off, if anything it might be a year or two older than that. Just fyi, at that age it almost certainly has a 2 1/2” chamber, and may have been designed with lower pressure shells. If you want to shoot it you might have a shotgun smith take a look and check barrel wall thickness, and I would look at some low pressure shells—RST makes them just for older guns like that.