One thing I would suggest is that you try to give her the benefit of the doubt and give her a chance to prove that reputation wrong. (Keep in mind: she may have ‘heard’ about your son too–teachers talk; wouldn’t you want her to give him the benefit of the doubt and a clean slate instead of holding past stuff against him?)
Teachers often get ‘reputations’ that are sometimes unfair and unfounded and due to circumstances and situations where we don’t always have the real story (as Dr. Phil says, “no matter how flat the pancake, there are always two sides!”). Also, there’s a chance that she’s recognized her need to change and has made a commitment to do better/differently this year. You don’t know.
So my suggestion is that if your son winds up with this teacher, (or with any teacher he winds up with), you approach her with a clean-slate mindset right from the get-go: let her know that your goal is to find a way to make this year the best year yet for your son (and for her) and that you welcome her input and suggestions. Let her know how to contact you with questions and concerns (and even find out what her favorite beverage or treat is so you can surprise her from time to time!) If you view her (and treat her) as an ally and a valuable member of your parenting team, she will be much more likely to rise to that.
Hope this helps.
Parenting Coach, school counselor, author, mom of adult son with ADHD