Meaning
Nine o’clock on a clock face, with the hour hand pointing left to the 9 and the minute hand pointing up, forming a right angle that mirrors the three o’clock face.
Nine in the morning is the textbook start of office hours, and nine at night is a common time for calls or a cosy show: “Opening at 🕘 tomorrow, come early for the best seats.” In schedules it sits nicely beside 💼 or 📞.