The Simple English Wiktionary has a definition for: nine.

9 (IX) is a common year of the Julian calendar which started on a Tuesday.^[1] According to the Gregorian calendar, it started on a Thursday.^[2] It was the 9th year of the 1st century.

• Illyria is turned into a province after a revolt has been defeated.
• The Rhine River is established as the boundary between the Latin and German speaking worlds, following the defeat of the Roman army, under the command of Varus, at the Battle of the Teutoburg Forest.
• Ovid is banished to Tomis.
• Pannonia (modern-day Hungary) submits to Roman rule.
• In order to increase the number of marriages, and ultimately the population, the lex Papia Poppaea is adopted in Rome. This law prohibits celibacy and childless relationships.
• Roman finances become strained following the Danubian insurrection, and Varus' defeat in Germany. This results in the levying of two new taxes: five percent of inheritances, and one percent on sales.
• Ovid completes Ibis.

• Wang Mang founds the short-lived Xin Dynasty in China (until 25).

• November 18 - Vespasian, Roman emperor

• Publius Quinctilius Varus, Roman general, at the Battle of the Teutoburg Forest, said to have committed suicide