Wow! What a social discussion this is.
I don't have the answers, but can offer some points of view to this.
I am a manager of a community football club men's team, and have been heavily involved in this club located in a low social-economic environment. The team I work with has grown up in the club and area from ~5 year old boys I knew 18 years ago to now. I have a couple of lads in my team that would easily fall into this gambling trap (and some have, but to a lesser extent - one lost NZ$6,000 a couple of years ago) if given the monetary and time freedoms that professional footballers are afforded. I have tried to help my players, but as I say, I don't have the answers.
I do think that giving young professional players a "job" outside of football when they start on their career would be a useful step, not only in their development, but in the relationship between the club and it's local area. This could be helping out at community sports clubs or orginisations or with schools, care givers or other groups that are usually struggling for staff and funding. Make it part of their contract and pair them with the entity for a year (maybe with incentives included in the contract).