The Zombie Stack Exchanges That Just Won't Die
In the morning (more often in summer), from 7AM to 9AM my books get almost direct sunlight.
Is there any solution to this problem other than just:
Nicolás
You may want to look into a concept of 'passive solar' architecture. A common solution for this would be some sort of planting outside that is of the height so that it blocks the sunlight in the early morning, but allows it to come through when the sun's higher in the sky. This is particularly useful for problems in the summer time, as it'll shield the house from light, but when the leaves die back in the winter it'll let more light through.
You can also use window screens to limit the total amount of light that comes through the windows (possibly only partial decorative screens that cover the upper or lower portion of the windows; I've seen the lower ones used to shield house plants from too much sunlight). You could use this in conjunction with the plantings, if there were some areas that hadn't yet filled in their foliage.
A third option would be some sort of louvered screen that would allow light through when the sun was higher in the sky, but block it when it's at lower angles.
I highly recommend solar shades. These are roll shades, like the traditional ones, but are made of special fabric which blocks heat and a lot of the light which damages your books. Since the damage to your collection seems to be happening early in the morning, before opening (?), make putting down the shades part of the closing duties for your staff. Those opening the next morning can raise the shades before opening the doors to your public.