Absolutely NOT

…He’s 9 years old. His mind is incapable of digesting the topic.
Truth is sometimes best revealed little by little.
The bigger question is whether any of the truth has been revealed at all.
A nine-year old, strictly speaking, is not incapable of understanding how sexual intercourse takes place, nor incapable of understanding what a condom does. He is not, however, prepared to get a fire hose blast of information about human reproduction, which is what it would take to properly explain a condom to the vast majority of nine year olds. There is no way on earth a child of nine who has been shielded from essentially all knowledge of things sexual ought to be told about condoms on Day 1 of his sexual education. A child needs to get this information gradually and calmly, with some time to digest each new piece, in order to get the information in a non-traumatic manner. It is a huge mistake to think that we can get the information we need to know to navigate this world in a one-shot “The Talk” from our parents, let alone getting such a talk as a shot from the hip from one of our grandparents.
The Talk that needs to take place is between the grandmother and her daughter concerning why the daughter thought that deflecting a question about condoms to her mother in a public place was a good idea. Was this supposed to be cute? Was she afraid to talk to her own son about sex? What did she hope to accomplish by what she did? Did she not know that she could have answered something like, “The short answer is that it is something that grown men buy, not something for boys to concern themselves with. The long answer is worth talking about, but it is too long to be giving it between here and the cash register. Remind me later, and we’ll talk about it when we have more time.”
Since the bishops instituted the Charter for the Protection of Children and Young People, there are far fewer Catholic children who are utterly unprepared to, for instance, understand that they have absolute authority over their own bodies and that they can say “no” to anyone. There are fewer who don’t have any way to know that there are several adults in their lives to whom they can go if they have questions.
The main thing, which is the safety of children, is that they all know several adults they can go to with sexual questions and concerns without ever being made to feel ashamed for asking the questions. What if we don’t feel comfortable asking our parents? There needs to be someone we can talk to discretely, other than the default answer, which is our equally-ill-informed friends. This means that these questions need to be handled in such a way that a child will never develop a fear or dislike of addressing these questions to the adults most likely to give edifying and ultimately truthful answers. That is the main thing here: Make sure this young man develops a confidence that he knows where to go with sexual questions, not a fear or even a dislike of asking the very people he ought to turn to first.