This is a wonderful comment that juxtaposes any suggestion that requires buying a scanner. That said, I wonder if this works at the scale that OPs kid will be tasked with?
(also, why is this on-topic, strictly-procedural comment I spent 30 minutes writing downvoted? Hacker news, you are fickle)
I don't see it here, but even accepting the need to barcode/isbn all the books, I would like a way to pull digitized or high-quality spine images for a VR library that is fed from an ISBN database of what you want it stocked with, using a query for shelving/sorting. I fear that this is a whole new project, akin to the original good cover scans, but lacking even a starting point from publisher sites.