There are two ways of looking at this that don't require any additional inside information (or even any information at all):
[1] he is correct that (at least) this part of the 9/11 report contains shoddy investigation;
or
[2] he is lying in his teeth and President Obama is trying to cover up how he and Former Secretary of State Clinton conspired with their Muslim Commie friends to help the Saudis to murder American citizens.
Expect both views to be vociferously advanced over the next few weeks.