That's one of the things that often gets me about the experts there. They don't know how much they don't know.
The funny thing is that Newt has long been well regarded as a military historian for an amateur*. Especially on the Civil War. (Even though his books are alternate history fiction, he and his co-author (an actual history professor) researched the historical events first.) Even his conclusions, like the one in those tweets, can be fitting into his political arguments/worldview, it's not like he's wrong on the details. Japan did pull off a nearly perfectly brilliant attack. (Especially considering their status as a military power under 50 years prior.)
Also, Newt reviews books on Amazon, and he's written favorable ones about understanding bin Laden, although not on 9/11 itself, so...
It also appears that he wrote a series on the Pacific War with the first book focused on Pearl Harbor.
*He's actually not entirely, he has a PhD in history, but after being denied tenure ran for Congress and left academia.