Quoting waiting on little luna!:" i think many formula fed babies have problems with constipation often. i could be wrong though, i'm not ... [snip!] ... he gives you the ok just because there might be like...an easing into it process that you have to do? idk. i'm just rambling "
I've had 4 and none of them ever have.
She might be grunting and fussing for another reason. It could be her tummy itself. My DD did a lot of grunting and fussing and only pooped once a day, but she had silent reflux and that's what was causing it. If your baby is pooping and it's not thicker than peanut butter, then there isn't a constipation issue.
Keep in mind, too... 9 days old is still really young. Your baby is still trying to adjust to life on the outside. It could be over-stimulation. When a baby is over-stimulated, they will grunt, cry, fuss, pull their legs up to their tummy, etc. So the first thought is that the baby is in pain. In reality, she doesn't know how to soothe herself as she is so used to being rocked, held, shushed, etc 24/7 in your womb. You might just have to help her.