He needs to know, that secret or not, if it is something INAPPROPRIATE, he needs to tell you. You are his Mom, and he shouldn't be crying about something, just for a secret.
And if it is something dangerous etc., he needs to tell you.
You need to make sure that you understand... that he can CONFIDE in you. That is it NOT about punishments if he tells you a "secret" that the girl told him. It is about... coming to you, with problems... and that he can trust you.
For anything, anytime.
A child, cannot always handle, keeping things bottled up, much less keeping secrets. And you NEED TO TELL HIM.... that, he CAN come to you, with things that are bothering him or upsetting him... that others put onto him.
He is only concerned about getting in trouble, with you.
That should not be the point.
The point is: he needs to understand that he CAN TELL YOU, things. To confide in you, too. His Mom.
Because, as he gets older... there will LOTS of instances, that he will have seen/heard/done something, that may trouble him. And he WILL NEED TO HAVE, a parent, that he can come to... to "vent" to about it, or just to get their take on it. You, as a sounding board. For his friend or school problems or "secrets" or whatever.
My Dad, was the person I could confide in with ANYTHING.
My Mom was not. Because she was only concerned about if we were bad or good. And she was punitive. So I never would tell her, anything.
I couldn't trust her, to be "understanding" or nurturing.
But my Dad, was.
My late Dad, used to say that, IF a child has No parent that they can confide in or come to with "problems" and they cannot vent to any of their parents or talk about things... then WHERE and with whom, will they do that with? And the answer is: with other people outside the home. Non parents. And at other places.
So decide, what do you want your son, to do, and learn, from you?
And per any "secrets" or problems, he may have????
Kids need us, to be a point of reference and a point of help.
Too.
Not just a point of getting punished.
Do you want him to come to YOU with problems?
Or to go to his friends or whoever?
Even with just secrets, that he cannot... handle?
Also, his 9 year old female friend, is now a "Tween." A Pre-Teen. Tweens are from 9-12 years old. A 7 and 9 year old, are vastly different developmentally and cognitively and emotionally and physically.
So think about that.
I have a 6 year old and 10 year old.