He sounds like a very intelligent little boy. School academics must not give him much of a challenge and seem boring once he completes his work. So he takes out his frustrations in the comforts of home. By virtue of creating "mixtures" and assessing the ability of his body to fit through the cat door is genius. Observe what creative direction he might be interested in such as music, drawing, making things with clay or building 3D objects with paper, maybe even learning some form of creative dance. Perhaps you might think sports is better for a boy but truly, a creative endeavor will stimulate his mind, fulfill his tactile urge and nurture his spirit.
I know a guy who was very active as a young boy, at age 6, his Mom started him in piano lessons. 38 years later, he still plays piano and even guitar, has been involved in bands and even has taught music to children.
Please don't get all consumed with what seems a negative trait but look at what and how he gets into these situations and recognize a potential. All of this will require great attention and focus on your part so be prepared to do some work. It could be a lot of fun and something which can become a family venture. Maybe begin a singing night or creative work night.
Sounds like you are a very good parent, concerned and very loving and open for some ideas. If you have tried this already and it didn't work, then definitely talk to your doctor and see what they say. I am not for medications for myself and will not endorse them but I do not oppose others if they discover this as an answer. This is a case by case analysis, one that also needs much focus and attention.
Enjoy his spirit, his intelligence and remember, all messes are cleanable and not worth the energy that anger can invoke.
Peace and creative resolutions!!!
K.