[It's not stealing! It's borrowing! Just...without her knowledge or express consent...but still!]

I suspect they were for public reading, for learning about Grass-types, so there should be no problem in learning from her research. There's also one about how to avoid Ghost-types, and several talismans I'm not sure what are for.

[He's definitely not telling these were in a secret room behind the gym leader's platform, because he already dug a hole for himself when he admitted taking these wasn't an entirely lawful thing to do.

Kiryu shows the object he was talking about. Ofuda tags for warding ghosts. He already knows it's for warding -- Japan culture! -- but he's not sure it's as simple as that]