I wouldn't encourage him to place a bet as of the moment, not until he can stand on his own two feet where he already land a good paying and stable job. But, what I do as of the moment? I would teach him how to analyze the match; who will potentially win or who lose. I wouldn't teach him how to analyze the odds either as it might somehow give him the idea that could entice him in placing bets. Though, everything could be learned over the internet, but at least I did what I can do as a parent who does not want my child to get involve in gambling at an early age.
No parents should encourage their children to gamble, but when they ask about something like this, we should make them understand that gambling isn't good for them, it can be both financially and mentally harmful for them if they get involved and become addicted to it, so they need to stay away from it as much as they can. Once they get this right, then we can help them make the analysis but as you said, we should ask them not to place any bets.
What I said above can only be applicable if a child is obedient because they wouldn't say no to anything you say or think that you are lying only to hide something from them, but if the child isn't obedient and barely listens or understands anything, maybe it is also not a good idea to help them do the analysis or give them any tips about it because they will surely misuse that information on your back.