Is there a legal fight against the school’s resource officer for putting my son in a handcuff after slamming his books on the floor?

It would nice to know all the facts, from the teacher, from students and from police before answering a question like this.

I would set up a meeting between the teacher(s), the officer, the principal, and the school administration. I do not think that behavior is appropriate. However, since kids are much more verbal and aggressive than when I was a kid, I don't think you should DO anything else until you learn the complete truth.

Yes, that's assault and battery.

It depends on whether your son did anything to justify being handcuffed. I would need to hear the officer's side of what happened.

Doubtful. The act of slamming his books on the floor could be interpreted as exhibiting the potential for an act of violence. The resource officer will claim that he/she needed to use the handcuffs to restrain your son and take control. As for the threatening by the teacher, ask for a face-to-face meeting with you, the teacher and a school administration official to calm the situation down and get it to stop (no accusations or raised voices). Follow up with a letter summarizing the meeting and stating that there are to be no further such threats.