He reportedly died peacefully of disease + natural causes, not coalition bombs.
I'm not convinced, that would be more likely to be intentional misinformation/misdirection. If he'd been dead for so long there would've been very little real gain to be had reporting his death now.
The case went cold for a long time, if the reports on the BBC are to be believed, people became aware of where he might be around a year a go but as these sort of things take time progress was slow, and, the weren't sure he was inside the compound until they got inside.
The only way for these reports to be proven false would be for AQ to provide proof that OBL died years ago, which they wouldn't even if they could. They could release another OBL video, but again this could be forged easily so would prove nothing.
People will have to take the story on face value, either believe it or not.