a 9 hour interview seems realistic but it also seems like that would be broken up over 2-3 different days.I read all of these stories from my news feed and they interviewed Patrick Graham for a reported 9 hours as well. I thought that was an awfully long time. If you were down to business, you can probably wrap it up in 3 or 4 hours, have a handshake agreement and let the bean counters sort the details.
You could be right though that his ask was too high. The Wilfs are not cheap. I suspect O'Connell came in there with a vision that impressed them. A new, younger breed of coach is having a lot of success. How they relate to players is different than in the past. KOC fits that. Harbaugh does not. I think it's intriguing and a total break from what they've done previously.
My longest interview was about 2 hours and it was not for a million dollar job.