I saw I am David at my Catholic high school 7 years ago and I really liked it because I even told my mom about it and then we rented it and watched it with our family, but it has been such a long time since I last the film, so I was wondering if there was a Catholic or at least religious message in the film. Thank you!
If it is anything like the eponymous novel it is based on, then the answer is 'Yes, sort of.'
Briefly, David was brought up in the prison camp by a Christian prisoner. Throughout the book he demonstrates a simple faith in the 'God of the green pastures and still waters' (reference to Ps. xxiii).
However, at one point, David converses with a Catholic priest, and he is not sure whether the God he prays to is the same as the priest's God.
Thus, the author seems to express a generalized theistic worldview, rather than a specifically Catholic/Christian one.
Hope that helped.
I saw it recently. I do not recall an overly Catholic overtone; however, depictions of Catholicism are positive and/or neutral, rather than negative (as is the case in most movies!)