Hes acting like the victim.
You dropped his book, he had a hissy fit. Threw away your water bottle, and then emptied out your backpack.
If he just kept it at kicking your water bottle, then it would not of been a serious issue. But he went to far by Throwing away your things and emptying your backpack.
Did you try telling him not to drop his book just to get attention?
Also, next time you see him, you should throw away his book and empty out his back pack to "Prove a point"