Not here to judge, but if you were really that worried, perhaps this is a question you should have asked before you got him..?
Anyways; I cannot claim extensive parrot experience, but i read a lot, and there seems to be enough consensus that things like this varies greatly between them all individually.
It depends on how they were weaned, how social-ised they are and if they have chosen to be a "one person bird", and also plenty of environmental factors that may promote or discourage hormonal or breeding behaviour.
By the way you describe him you are off to an amazing start. And he shouldn't "crumble over time" purely because he grows up, as long as training is consistent.
If you ever do have problems, you should be able to manage them quite easily with appropriate training and handling, controlling the environment, and be able to redirect any unwanted behaviours.
(and coming back on here would definetly provide you with much more detailed help on whatever specific issues there may be)
My boy is not loud at all, and i don't know about other eclectus's habits, but they dont seem to have a habit of "showing off" and screaming routinely like a lot of cockatoos are known to... (by routinely i do not mean excessively either, i just mean on a regular basis at a regular time)