I would definitely grade it under 8.5, but as others have mentioned, the cranked brightness makes it tough to see the details. Given the current images, I'd say it's a ballpark 7.0. If you could get scans of the front and back using similar settings that you used on the interior pages, that'd be better.
Of course, this is just my humble opinion. I may be biased, but it's a fantastic book in any condition.
