Good schools near Vrije University

they are fine, just find a place and enrol, they are local schools, St Julien a bit more favoured.

Thank you for your answer.
Let me explain more. We are a family with a 8 years old right now. We don't know where will find something to rent. Our budget isn't very big, I will be a master student for 2 years and my husband will work from home, that means he will come with us in Belgium , but his salary is around a 1000 euro. I think I should find a job.
If we will find a flat to rent in Laeken for example , is that a problem to enroll him at Institut St Julien or I suppose to live in that area?
I want for my son a school with a good level of education.
Why St Julien is better?
What will be another good choise?
Is too late now to find a place at a good school?
We were there 1 week in September this year and visit these 2 school.Can we enroll him from our country, Romania ?

Why on earth would you rent in Laeken if you are going to VUB?
Rent near school and university.
You cannot be fussy when your son is entering school 5 years after most other children enter school, getting any place should be priority, then choosing between places should come after. Both these schools will be used to immigrant children.
It's impossible to recommend other schools, there are 300 of them in Brussels. Just rent near to home. That area is not too expensive. You can get a 2 bed apartment for 700-800 a month, you're unlikely to get cheaper in Laeken, but if you want to live in Laeken, then choose a school there.
You can reserve a place from abroad, but you have to ask each individual school.

I thought Etterbeck and Auderghem are more expensive than Laeken. Can you recommend me good schools in the mentioned areas below? Thank you

As I said, it's not a matter of good schools, it's a matter of finding any places.