We can't teach about everything to a kid and not even to an adult for that matter. I do agree we have to create more awareness about addiction in general as early as possible so that more people have chance to get out of this swirl but it's not only the responsibility of education system.
It should be done combined by efforts from all the side, mainly from parents in my opinion.
I observed that the issue with some parents is that they form too busy and more serious with their jobs & occupation forgetting to perform their parental relationship and responsibility very well to their kids, they always leave the kids with nanny and assume that the nanny can teach the kid all the thing they should know. Like you said, it should be a combination of effort, kids doesn't just learn in school but I think at their tender age, they learn from everywhere and at some point, they can even learn more from what is happening around them and because they spend most of their time at home, they learn more home.
There is a need for work-life balance so that parents can balance their careers and families. Unfortunately, most jobs do not allow parents to provide their children with the attention and training they need to succeed in life. A child's upbringing can be compared to a system, and just as all parts of the system are required to play a role in the proper functioning of the system, so are parents, schools, and even churches expected to play roles in making a child a better person in society.
I recall that sex education was not previously taught in schools. However, due to the recurrence of unwanted pregnancy and the spread of sexually transmitted diseases (STDs), sex education was introduced to assist individuals, particularly teenagers, in avoiding these sexually related challenges. So, now that gambling has become a global issue, teenagers and adults should be guided through instructions and programs from parents, teachers, and even guidance counselors to provide teenagers with concrete information on how to avoid gambling related even before they even engage in it.