Just ask if you can volunteer in class.
And typically, parents (at least at my kids' school), of Kindergarteners... always walk with their child to the classroom, then go into the classroom with their child, get them to their desk and say their goodbye's etc. And the Teachers at my kids' school, have NO problem with that.
Some Moms are there in the classroom for awhile, and help, too.
IF the Teacher, needs help.
Per the evening introduction you went to... these are not typically a social. It is, time constrained and the grade level Teachers typically give an overview... of the school/grade level, introduce the Teachers etc. It is not a "meeting" nor a time to socialize or have all the parents, ask each Teacher questions. That would take, all night to do so.
And being there are 6 Kindergarten classes, that is many parents to attend to, at these "orientation" type introductions.
And at these functions, at least at my kids' school, they may pass out flyers to the parents with, information on it. And tell you about the curriculum etc.
Until your child, is actually assigned to a Teacher and classroom... you will not know who your child's Teacher, actually is. Unless the class lists were already made, prior to your going to that introduction meeting that you went to in the evening.
And it is true, that if all the Moms... wanted to just "attend classes" and "observe" the Teacher, then what? Yes, it will or may disrupt all the kids... remember that the kids are getting used to, "school." And the Teacher... has to, get her classroom/kids into a routine... and get them used to things, too. It is hard work.
Then, if you observe the Teacher and the class... and attend classes, then what? If you just want to be in the classroom... then Volunteer.
But keep in mind, that per each child, they make act differently if their Mommy is there. And they may not then, listen to the Teacher. Or they may... cry... if you are there, etc.
With my kids when they were that age and even now... I ALWAYS INTRODUCE MYSELF to the Teacher, and extend my... volunteering to her. I don't just wait... for the Teacher to come to me. Remember, she has TONS of kids and parents... to remember. And she cannot possibly go up to EACH parent, and get all social with them. As soon as school starts and the kids enter the classroom... a Teacher, HAS TO, be on top of things and get the kids rounded up and settled in, and begin her classroom routines. It is BUSY. Believe me. I am there, in the mornings at my kids' school... and it is BUSY and the Teacher is BUSY. She cannot... possibly, stop and chat with each Mom... that may be there. Because, she has to keep her eyes and ears... on her students. Constantly.
Just ask your child's Teacher, if he/she needs Volunteers.
But, it is up to the Teacher.
Some Teachers do not. Some do.
But the thing is: you seem to want to "observe" the Teacher and her classroom... in order to see if this is the right place for your son. BUT, he would already be... enrolled, there, once you do that. And school would have already started. So if you find it is not the right school for him... you will pull him out and put him in another school?
Or will you ask that he be put into another Teacher's classroom?
That would mean, that you'd need to observe the classes/Teachers, for 6.... rooms. Being there is 6 classes in that grade level.
School, is also about realizing that every year, there are different teachers that will be teaching your child. All sorts of teaching styles and approaches and classroom dynamics. But, in all grades/classes, the school's curriculum... is a certain way.
And each year, a child adjusts... to having a new and different teacher... and classroom dynamic. Unless, you are not happy with the school, overall. Then in that case, you'd need to find another school entirely, for your child.
This is Elementary school. Not Preschool anymore.
And remember, that NO Teacher/classroom, will be perfect.
But a child also has to learn... to adjust.... to new and different Teachers and grades, EACH year. And yes, different teaching... styles.
This is how elementary school is.
Then there is the grade level curriculum... of which, each grade's requirements, are different.