If my child wants to deny a visit once in awhile with other parent, what can I do?

Illinois. My daughter’s father stopped seeing her 5 months ago. He then took me to court for visitation. I agreed under certain terms. We have come to an agreement. I have full custody and he agreed to that as well. Our daughter feels forced to go and gets upset because she isn't used to being around him. He has kept her over night once in the past year. She loves her father but just isn't wanting to do overnight stays. She is 9 years old. My ex was arrested for domestic violence/bodily harm to me and I'm worried about things getting out of hand. Do I have to force her to keep going to visits? Can she deny a visit herself? She requested herself to not go with her father and he simply didn’t care how she felt. I'm just worried about her and feel helpless that I can't help her with these emotional issues.