Basically mods work by changing or editing existing game code, there’s no code that would allow for this type of change.
I doubt it will be added either, as it would be easy to exploit on long routes that involve ferries. Also I can’t see them adding something thing intentionally unrealistic. In real life, if you arrive before you window opens, you have to wait. I know a driver who arrived 24hours early because of a timing mix-up. The poor guy had to park up on the street and wait for his delivery window the following day.