Ridicule me all you like. It doesn't change the fact that I saw TUC in theaters twice in '91-'92, and the line was there both times. Yet, there is no evidence of it ever existing in published scripts of the film, or in any video release, all of which would have been overseen by Rick Berman in his position of Head of All Things Star Trek during that era.
You dreamed it.
Can you imagine the expense and red tape required to recall all prints of the film to remove said line... not to mention getting Dr Pulaski to erase our memories?
lines about being a captain towards the end, but they were about Sulu:
By God, that's a big ship.
Not so big as her Captain, I think.
The fifth draft, still with Saavik instead of Valeris, has this early scene:
Plot a course for Kronos, Lieutenant.
I'm still in the chair, Lieutenant.
Other reactions. Kirk has taken command.