In the academy you'll get a player with 3 stat across the board. Age is determined by the initial investment.
This is also the only way to get young players.
The scout system only gives you players, who run out of contract. Your investement determines the elo range based on how much other people invest. So this is kinda random.
So academy training is good early on, cause you won't have enough coaches to train a five men squad.
Coaching in your main team is more effective though.
Oh and when using the academy, never do anything else than 1KK / 100K