Its not possible to leave it out of instruction. The purpose of education (as it currently exists, and as they claim it to be) is to prepare children to function as adults in society. Some kids have racist parents, some kids have homophobic parents, some kids have misogynistic parents, some children are abused at home or are taught hatred and bigotry. The state has an obligation to advocate for the rights of children, because children are vulnerable and are not capable of removing themselves from an abusive home. Its the entire reason protective services exists in theory. Children are not possessions, you cannot just do whatever you want to your child, your child has the same fundamental human rights as any other human being. And like any other vulnerable human being, society has to ensure that the rights of children are being respected.
Children who are outted to their parents can face homelessness, abuse, psychological torture in conversion camps, ostracization from their friends and communities, isolation, manipulation, and bullying. It can end lives. Children can and do die because they are outted to their transphobic parents. As I said, society had a responsibility to ensure that the rights of children are being respected. The right to safety and security is one such right that is compromised by forcibly outting children to their parents. Educators should ALWAYS have to listen to the child and take no action without the permission of that child. Because children are people, and people are supposed to have rights. Children are not possessions of their parents, they are human beings who have fundamental rights the same as any other human being. The state should not be considering parents at all in this equation. The only person who needs to consider whether or not parents should know would be the children in question.
Children should also be taught about the existence of gay and trans people as part of regular education. The state has an obligation to provide proper education to everyone. Proper education should take steps to mitigate bigotry. Anti racism should be taught in schools, feminism and women's rights should be taught in schools. It is much the same with gay and trans rights.