My rottie just turned 9 months and i take him for a walk at the park and bike trails, but there are some dogs who are not on leashes who approach him.
There's this one dog who i wanna say is a bully dog and always approaches my dog, but he stops and he barks and growls at my dog, but my dog stands tall and doesn't look at him. But what i wanna know is the other dog trying to test my dog to see what he does? Does how he acts mean my dog is about to stand his ground with this bully and if anything ever happens will my dog stand his ground? Is he standing his ground by the way he stands tall?
He's not scared of other dogs but what i wanna know is if he's communicating in some way with the bully dog, or what does it mean in other words i wanna know what to expect for a dog his age.
At 9 months old your Rottweiler is still a puppy, but he's an adolescent rather than a baby. He's just beginning to feel his 'guardian' instincts and for his age he's showing good control and appropriate behavior.
It's important to always keep your dog leashed when out in public, but it's natural for a dog who is on a leash to feel defensive if approached by an unleashed dog. The fact that he stands up tall means he is preparing to defend himself (and you) if necessary, but the fact that he doesn't make eye contact with the other dog means that he's trying not to challenge him or escalate the situation. A mature response.
Rottweilers are natural guardians, but they aren't (or shouldn't be) indiscriminately aggressive and don't generally start a conflict, or respond unless they feel it's absolutely necessary.
I'd recommend that you take a look at my Rottweiler Temperament and Rottweiler Behavior pages as they have lots of information that I think you'll find interesting and helpful.
Don't ever encourage your dog to act aggressively, or defensively, that will confuse him and make him unpredictable. Don't doubt that he would defend himself, or his home/family, if necessary, but don't transfer any feelings of anxiety or combativeness to him either. If anything an adolescent dog is more inclined to over-react than under-react, and your pup is showing solid temperament and the right behavior. Be proud of him.
Best of luck.