When I would catch Sydney or Chloe going where they weren't suppose to I would also say
"NO" (loudly but not "scary") and take them to where they were suppose to go ( pee pad or outside) and say ,"potty outside or potty on your pad" ( one is outside trained the other pad trained) If they finished there I would praise them and treat for doing it . If they didn't I would put them in their crate and then try again in 10/15 minutes or so , they usually went.
Every time I take them out of the crate the first place they go is outside or to the pee pad. So they know what is expected. I still do this and my older dog is 3 years old. She will go right to the door and wait. Chloe (8 mo.)is pee pad trained so I take her to her pad. I think it helps to let them know what is needed before they get fun time. They make the connection ..O.K> get out,go pee,have fun
....get out , No pee...no fun
He most certainly should have freedom , no one wants to be confined all the time......BUT supervised freedom only
Never alone unless he is in his playyard/crate. If you want to have playtime with him you just need to let him pee first . He also may have to go more while you play because he is excited. keep him in the same room as you for playtime and keep pads around so if he does have to go he can run and use it and get praised for it.
What worked for me was having lots of pads at first to give Chloe every opportunity for success , then I slowly dwindled the pads down to one or two , and she knows where they are. The more opportunity the have to get it right the better they will do.