By 9 months, typical development includes babies becoming shy around strangers, having favorite toys, copying sounds and gestures, pointing, playing peek-a-boo, putting objects in their mouth, crawling, and standing with support. Atypical development may include babies not recognizing familiar people, not babbling, not responding to their name, and not being able to sit or crawl without help. The document provides an overview of typical and atypical development across social, language, cognitive, and physical domains for 9-month-old babies.