Just found this random clip of an interview on Breakfast dated from 2004. I notice the programme finished at 9:30. Did Breakfast use to air later than 9:15 in those days? It's dated as 23rd April which was a Friday so it wasn't a weekend edition and with it being April i can't think of any special reason to the programme being extended.
Breakfast did run until 9:30 at that point, as shown by a BBC One schedule from that day.
BBC Genome seems to suggest that from Monday 26 January 2004
, the first weekday after Kilroy finished, Breakfast was extended to finish at 9:30; however, this only lasted until Monday 5 July 2004
, when Breakfast moved to finish at 9:15. Of course, when Kilroy was still running, Breakfast used to finish at 9am.