Sorry to hear about your childhood experience. I hope you both are ok now.
It is very unfortunate for a 9 yo to face abuse from one parent and the other parent not able to protect the child from the abuse. What would one do depends on the circumstance. Here in US kids are taught at a very young age to speak up and bring it up with school authorities if there is any kind of abuse involved at home. Still some kids tend not to bring it up. It depends from kid to kid how they react. School staff are taught to watch for certain kind of behaviors in kids and in cases where they suspect abuse the authorities intervene try to find out what is going on etc. I know about a family whose kid suffered an accident and when they took the kid to the hospital, a social worker was assigned and the social worker interviewed the kid and the parents to make sure it was an accident and there was no abuse involved. With all the awareness involved there are still many many cases where it don't come to surface. Some kids who undergo abuse grows up to not become bad themselves but more often they then become the abusers and the cycle continues. In Maya's case unfortunately that's what we are seeing where she has become like Ashwin and controls and manipulate the people around her. She needs therapy to first find out what is wrong with her and do further therapy or treatment to fix her problem. unconditional love is not the answer. Even if Vandana accepted her and if there was no Sanj inAdjun's life at some point she would have started acting the same way and would have ended the same way cos it is not possible for Arjun to lead a life that she expects i.e. A life with just maya and her wishes. It is not humanly possible in reality to live like that. She needs to seek medical help.