Q. My 9-month-old isn't crawling yet, but my niece, who's 8 months, is. Could my baby be developmentally delayed?
A. I doubt it. Crawling is an extremely variable milestone; some kids will do it at 6 months, some will do it closer to a year, and some kids never do it -- they shuffle around on their bottoms or bellies, or go straight to walking. That's what my son Zack did: At 9 months he learned to pull himself up to stand, and then he'd yell until someone took his hands and walked him to where he wanted to go!
What's more important: At 9 months your child should be able to sit independently, pull himself up on all fours, and bear weight easily on his legs while holding on to something or someone. He should also be interested in getting around -- somehow. If none of these are the case, you should talk with your pediatrician to make sure there isn't a problem with his muscles or his development. Most likely, though, he's totally normal -- and simply reminding you that he's his own person, who will do things when he's ready.