Yes, a 9 lb baby can wear newborn clothes. Newborn clothing sizes typically range from 0-3 months and cover babies up to 10 lbs or even more. Although some babies may start out smaller than others, they will eventually grow into the size given on the clothing tag. It is best to buy clothes that fit your little one now rather than buying too many large sized items as they will quickly become too tight and uncomfortable for them to wear.