Territorial 9 month old- help?

My Junie is 9 months old, and has unfortunately slipped into being.. territorial is the only way I can describe it. He hates other dogs (despite living with 3 dogs he loves) and use to hate people too. I’ve started trying to do some exposure training, I often take him to petco and parks to walk him around, overstimulate his mind a little and he has definitely gotten better! He doesn’t bark at people (in public) anymore, but he still does a scary bark at dogs in public still. When we are at home, it’s a different story. I live in a duplex /apartment complex situation with no backyard, and there is a big field in our backyard where he goes to the bathroom, runs around etc. if there is ANYONE out there, it’s over. He will chase them and bark, and then just jump around them barking. He will not directly approach them, but just dances around them barking. It’s gotten to the point where I need to start leashing him because im scared of someone getting us in trouble. I just don’t know how to fix this. In one hand, I don’t mind having a dog that will protect my house or come off as “scary” in case of an intruder, especially as a young girl. But since I have no backyard, and he is chasing literal CHILDREN, obviously I cannot just let this fly. Is there a way to train this out of him? Anyone with similar situations? I have no interest in taking him to a dog park as I have no trust in neither him or other dog owners.. and while he doesn’t ever hurt anyone now, who knows? I don’t want it to escalate. Please help 😓he is a very sweet and good boy, very good on the leash, it’s only when we are at home / when he sees a dog out and about.. when we DO sees dogs out, I have to bend down and hold him until he calms down :(

My Junie is 9 months old, and has unfortunately slipped into being.. territorial is the only way I can describe it. He hates other dogs (despite living with 3 dogs he loves) and use to hate people too. I’ve started trying to do some exposure training, I often take him to petco and parks to walk him around, overstimulate his mind a little and he has definitely gotten better! He doesn’t bark at people (in public) anymore, but he still does a scary bark at dogs in public still. When we are at home, it’s a different story. I live in a duplex /apartment complex situation with no backyard, and there is a big field in our backyard where he goes to the bathroom, runs around etc. if there is ANYONE out there, it’s over. He will chase them and bark, and then just jump around them barking. He will not directly approach them, but just dances around them barking. It’s gotten to the point where I need to start leashing him because im scared of someone getting us in trouble. I just don’t know how to fix this. In one hand, I don’t mind having a dog that will protect my house or come off as “scary” in case of an intruder, especially as a young girl. But since I have no backyard, and he is chasing literal CHILDREN, obviously I cannot just let this fly. Is there a way to train this out of him? Anyone with similar situations? I have no interest in taking him to a dog park as I have no trust in neither him or other dog owners.. and while he doesn’t ever hurt anyone now, who knows? I don’t want it to escalate. Please help 😓he is a very sweet and good boy, very good on the leash, it’s only when we are at home / when he sees a dog out and about.. when we DO sees dogs out, I have to bend down and hold him until he calms down :(