Firstly, I want to give you a caveat. Every parent in my (nearly 20 years in family law) experience says that their child is remarkably intelligent and mature when the child's views and preferences support what that parent wants.
Please read that again. It's important. Family court judges know this.
Nine is very young to rely on the child's views and preferences. But if you're confident that the child will tell a neutral third party like a lawyer or social worker appointed by the court to gather that evidence, that the child wants to have half time with you or more, then you have nothing to lose by making a request from the court for half time and for appointment of the provincial Office of the Children's Lawyer. While children never get the right to unilaterally decide custody and access issues between their parents, the court often wants to have their input. And at age nine, the child is well within the "range" of ages where the court will want to appoint for the child.
You've asked if father could deny access back to what's in the order. Technically, yes he could. But you've had a new status quo for a long time by mutual agreement so I really doubt that father could make you look bad in court and try to have you declared to be in contempt.
You really need to consult with a decent family law lawyer in your area for a consult to find out how the courts and judges in your jurisdiction treat these issues. I can't tell you that. This may well be a good time to bring a variation motion to the court.
I can't tell you the odds of success. It depends on the evidence, and the child's views and preferences as expressed to a neutral third party is just another piece of evidence. It's up to the judge to decide how relevant and reliable that evidence from the child is.
Does that make sense? I'll await your question or comment.