when will the courts listen to a child?

My child is 9. When it is time to go and spend a month during the summer with my ex my child does not want to go. When she is visiting she is left at home with her step Mom who works midnights and then leaves the child unattended watching TV while she sleeps. Among other things they pick on her for missing me and punish her by sending her to her room when she says she wants to go home or when she says she misses me. Tell the child that she is a spoiled brat. They have even said this to me! These are just a few things. No physical abuse. Just mental. My child wants me to get her a lawyer. What can I do to help her. She wouldn't mind visiting for a short period of time say a week or two...with prodding from me. Is that too unreasonable? Do judges allow this type of thing?