Aiyoo jangan risau sangat lah, this happens quite a bit actually, a few of us went through the same thing and it usually just means ovulation came later than expected, so the baby is developing perfectly fine, just the dating was a bit off. Your last period date is only an estimate anyway, so if the ultrasound shows 9 weeks 6 days, the doctor will just adjust your due date based on that, it's more accurate than counting from LMP alone, and honestly this is super common and nothing to worry about. Best thing is just check with your OB at the next visit to make sure everything else is measuring fine, but I'm sure baby is doing great!