Question about parenting

I have a son and a lot of the time he misbehaves he is eight years old and the behavior has got to an extreme he is disrespectful today the way he spoke to me was disrespectful and he would not do things he needed to get done. I spoke to him about the importance getting his work done and he grabbed a large kitchen knife and started slashing the house cutting the house and threatening to kill me. I told him if he did not put the knife away I would call the police he then put the knife away after swinging it towards me and he called me profanities he damaged the house he ripped things off of the walls and I asked him to go to his room and think about what he has done he said no and is walking around the house stomping throwing things.

What would you do in regards to parenting an eight year old boy? what can we do because he is still young and is growing older. I don't know or understand what is going on at age eight why he's so angry why he does not listen he tells me he is the boss and say's" I don't care I don't have to listen to you" it's frustrating because I want our family to be successful if he is able to do simple chores done and talk to adults with respect get his homework done I can help It's daily responsibilities and knowing how to talk to your mom with respect and not having attitude or talking back and spending time not doing what you were supposed to do there's like a power struggle where he wants to be the leader the boss and do what he wants.

What would help this family and what can help him what parenting advice can you share