Pediatric ATI Practice Exam 2025 – 400 Free Practice Questions to Pass the Exam

At 9 months of age, infants are typically developing skills related to movement and social interaction. Crawling proficiently is a key milestone for this age. Many infants begin crawling around 6 to 10 months, and by 9 months, they often have improved strength and coordination that allow them to move around their environment more effectively. Crawling not only enhances their motor skills but also supports cognitive development as they explore their surroundings.

While walking with assistance can occur around this time, it is not as universally expected as crawling. The use of two words in a sentence typically emerges around 18 to 24 months, and while playing peek-a-boo is a common game for infants, it may not be as significant as proficient crawling in terms of developmental milestones at this age. Thus, proficient crawling is the development milestone that best aligns with the expected abilities of a 9-month-old infant.