I'm interested to see how this turns out under Florida laws and considering he's a juvenile. What worries me is the statement: "The final shot hit the man in the leg as he was hopping the fence, the boy said." I think for an adult that might be a problem. Not sure for a juvenile, who are usually held to a lower standard. As well I'm not sure how that is affected by their "stand your ground" law, which I think means you have the right to protect your property which seems like it would include using reasonable force to stop a person who is stealing your property even if he is already outside running away. For an 11 year old kid against an adult armed with a gun, I think shooting him as he is running away is reasonable if the "stand your ground" law actually allows this.
Now on moral grounds, is it morally reasonable to use deadly force against a person that is already running away over the theft of property? For an adult, I think maybe not. For an 11 year old kid that was just confronted by an adult thug with a gun, I think maybe he can't be held to the same expectations of clear moral thinking in that situation. And lets keep in mind, in this case it may have been legal for the police to have shot the guy as he was running away under "fleeing felon" policies if their department has such a policy. So it's maybe not so morally wrong as some might think. But we will see what the judge decides.