By his ninth month, your baby has settled into a predictable pattern of physical growth, although his particular pattern may be slightly different from his peers. Another part of physical development during the second half of his first year of life is the development of motor skills, so you'll also notice an increase in everything from his ability to get around to his ability to handle small objects with more dexterity.
Height and Weight
Physical growth in babies slows down between 8 and 12 months of age, so at 9 months old, your baby will not be gaining weight or growing in length as quickly as he was previously. The length and weight of a 9-month-old baby depends on the child. Boys this age are usually between 16 to 25 pounds in weight and 26 to 30 inches long, and 9-month-old girls are usually between 14 to 24 pounds in weight and 25.5 to 29.5 inches long. A 9-month-old baby's growth should continue to fall along the same growth curve as it did throughout the first nine months of life.
At 9 months old, your baby has begun to develop control over her body. She can likely crawl, roll and sit for long periods of time without support. She can likely also pull herself to a standing position while holding onto furniture by the time she is 9 months old, and she may be starting to push a walker or cruise along the furniture while in a standing position. If your baby is still having trouble sitting up or hasn't begun to crawl yet, talk to her pediatrician about having a physical assessment done to rule out any potential problems.
Fine motor control in a 9-month-old is generally good enough for him to grab objects in a pincer grasp between the thumb and index finger. This development makes it easier for the baby to feed himself finger foods, throw toys and shake a rattle. A 9-month-old baby also typically has enough hand-eye coordination to wave goodbye, and if you've been introducing baby sign language, he might begin to respond with gestures of his own at around 9 months of age.
Your 9-month-old baby's teeth may have already begun to erupt, or you may be noticing the first signs of tooth development right around this point. Most babies develop their top two central incisors between the ages of 8 to 12 months old and their bottom two central teeth between 6 and 10 months of age. Some 9-month-old babies will also have begun to cut the next two top teeth, the lateral incisors. Keep teething rings and cold packs on hand to help ease your baby's teething aches and pains.