I noticed that my 9mth old baby has been coming home with occasional bruises from infantcare. I checked with the teacher and she got very defensive and said that she;s not sure how he got it. What do you think I should do?

Bring it up with the head of the school. Principal etc. Ask for CCTV to replay. Straight up no bullshit. This is your kid's well being. Have no mercy in your pursuit for the truth, but have leniency when deciding who to blame.