German Shepherd/ Rednose Pit or Mountain Cur?

My dog's name is Brock. I got him from a breeder. I think he's half German Shepherd half Mountain Cur or pit.

His appetite is decent, he eats 6 times a day

For exercise, he gets 3 walks a day and plenty of play time.

Brock is just over 9 weeks old. We know his dad is full blooded German Shepherd and his mom is full blooded pit or Mountain Cur.

His litter was bred as police dogs but the breeder said he will be too big for police work.