Why? Books need not be unique books. There could be variations of the same book. For example, many books / scriptures were still being reconciled as recently as

Why? Books need not be unique books. There could be variations of the same book. For example, many books / scriptures were still being reconciled as recently as 100 years back and there are so many versions of ramayana available from one corner of Asia to another corner, that I would expect a respectable university to try to look at the variations and do some kind of lineage analysis. And also book may not imply a 1000 page book, it could also mean an 8 page manuscript. Does 9 million sound big, sure? But in the absence of other information, maybe we can debate the quantum of overstatement rather than just assuming that since we can't explain it, everything related to it may be fake. And last point, maybe there were 9 million books. What's a university if it does not have more than one book per student especially if they built that library over 700 years. Maybe each student had an annual journal which is classified as a book.