Did I just made a huge mistake?

I am a single parent, have been for 14 years. I have a 16 year old son and for the last 2 years his grades have been slipping. His dad is not a very big part of his life, he has never been reliable or dependable and according to him I keep my son under too close supervision, he says that our son is a man and needs more freedom. I switched him from schools per his request in hopes he would do better. 3 months ago his new school report card came with a 2.35 an improvement from his last, but not where he promised he would be. I gave him an ultimatum to improve his grades or he needs to move in with his dad. I got a progress report on Friday and he is failing one cl and has D's in two other cles. The low grades are due to missing ignments and the teachers gave him this 3 day weekend to complete them. Well I was checking his second essay today and found he plagiarized and I got really upset because he denied it. I told him he needed to get his act together and I would not let him play football anymore and he needed to get a part time job, or move in with his dad. He called him, and his dad says he can come pick him up on Wednesday. But I am afraid that if my son does not have someone constantly on his case he will just drop out of school, but then again he may just want some freedom. btw we live in Los Angeles.