I think this a reach to be honest. The police will know if she took the kids to school. There’s tons of witnesses every day that I drop my own kids off that could attest to me being there, let alone her kids are old enough to say.
The police clearly have enough of an idea that she was there to be pulling out expensive river searches almost immediately.
I’m not really sure why you think the 9.15am witness isn’t solid either? Police have established the last known sighting of her is 9.15am. It’s not being reported as a potential sighting. So that’s not a dispute, it’s a fact. It’s not unusual for police to appeal for witnesses, cctv, doorbell and dash cam footage, that doesn’t mean they have concerns about the witness, it means they want to build as big a movement picture as they can of where she went and on what timeline.