What gross motor milestone do children achieve at around 9 months?

At around 9 months of age, children typically achieve the gross motor milestone of sitting without support. This milestone indicates significant progress in a child's physical development, as it requires the development of core strength, balance, and coordination. By this age, most infants have gained sufficient muscular control to sit upright and maintain their position without needing to rely on external support, allowing them to explore their environment more freely and engage with toys and other stimuli.

Walking without support is generally achieved closer to 12 months, while running and jumping usually occur well after that, typically around 15-18 months or later. Thus, sitting without support is the appropriate milestone for a 9-month-old, highlighting their growing motor capabilities and independence.