The thing about Rooney was he was physically a 24 year old when he was 18 and was always going to have a short career (age wise) as by the time he was 28 his fitness was that of a 33 year old. Phil looks like he's 18 at the moment so throwing him in with 27 year old opposition players from the start is not a wise choice. He needs easing in.
Exactly, his development is being handled well. Too soon for him to be starting PL games but I expect him and Brahim to start all games in the domestic cups. Looks like both have developed physically since last season.