They probably did add a minute of content. I checked the Tivo recording clock when the credits started rolling, and it was at 1:00 – so it might have gone to 1:01 by the time it was done.
But if one’s recording shut off at 9:00 one definitely would not have missed anything.
My Direct TV DVR is a Tivo and it’ll record two shows even if there’s a time overlap. The only time it won’t do this is if I add a third show to the mix.