| 102677 | September 9 | Event | 1922 – The Greco-Turkish War effectively ends with Turkish victory over the Greeks in Smyrna. |
| 102678 | September 9 | Event | 1923 – Mustafa Kemal Atatürk, the founder of the Republic of Turkey, founds the Republican People's Party. |
| 102679 | September 9 | Event | 1924 – Hanapepe massacre occurs on Kauai, Hawaii. |
| 102680 | September 9 | Event | 1926 – In the United States the National Broadcasting Company is formed. |
| 102681 | September 9 | Event | 1936 – The crews of Portuguese Navy frigate NRP Afonso de Albuquerque and destroyer Dão mutinied against Salazar dictatorship's support of General Franco's coup and declared their solidarity with the Spanish Republic. |
| 102682 | September 9 | Event | 1939 – World War II: The Battle of Hel begins, the longest-defended pocket of Polish Army resistance during the German invasion of Poland. |
| 102683 | September 9 | Event | 1939 – Burmese national hero U Ottama dies in prison after a hunger strike to protest Britain's colonial government. |
| 102684 | September 9 | Event | 1940 – George Stibitz pioneers the first remote operation of a computer. |
| 102685 | September 9 | Event | 1940 – Treznea massacre: The Hungarian Army, supported by local Hungarians kill 93 Romanian civilians in Treznea, a village in Northern Transylvania, as part of attempts to ethnic cleansing. |
| 102686 | September 9 | Event | 1942 – World War II: A Japanese floatplane drops incendiary bombs on Oregon. |
| 102687 | September 9 | Event | 1943 – World War II: The Allies land at Salerno and Taranto, Italy. |
| 102688 | September 9 | Event | 1944 – World War II: The Fatherland Front takes power in Bulgaria through a military coup in the capital and armed rebellion in the country. A new pro-Soviet government is established. |
| 102689 | September 9 | Event | 1945 – Second Sino-Japanese War: The Empire of Japan formally surrenders to China. |
| 102690 | September 9 | Event | 1947 – First case of a computer bug being found: A moth lodges in a relay of a Harvard Mark II computer at Harvard University. |
| 102661 | September 9 | Event | 1513 – James IV of Scotland is defeated and dies in the Battle of Flodden, ending Scotland's involvement in the War of the League of Cambrai. |
| 102662 | September 9 | Event | 1543 – Mary Stuart, at nine months old, is crowned "Queen of Scots" in the central Scottish town of Stirling. |
| 102663 | September 9 | Event | 1561 – The ultimately unsuccessful Colloquy at Poissy opens in an effort to reconcile French Catholics and Protestants. |
| 102664 | September 9 | Event | 1739 – Stono Rebellion, the largest slave uprising in Britain's mainland North American colonies prior to the American Revolution, erupts near Charleston, South Carolina. |
| 102665 | September 9 | Event | 1776 – The Continental Congress officially names its new union of sovereign states the United States. |
| 102666 | September 9 | Event | 1791 – Washington, D.C., the capital of the United States, is named after President George Washington. |
| 102667 | September 9 | Event | 1801 – Alexander I of Russia confirms the privileges of Baltic provinces. |
| 102668 | September 9 | Event | 1839 – John Herschel takes the first glass plate photograph. |
| 102669 | September 9 | Event | 1850 – California is admitted as the thirty-first U.S. state. |
| 102670 | September 9 | Event | 1850 – The Compromise of 1850 transfers a third of Texas's claimed territory (now parts of Colorado, Kansas, New Mexico, Oklahoma, and Wyoming) to federal control in return for the U.S. federal government assuming $10 million of Texas's pre-annexation deb |
| 102671 | September 9 | Event | 1855 – Crimean War: The Siege of Sevastopol comes to an end when Russian forces abandon the city. |
| 102672 | September 9 | Event | 1863 – American Civil War: The Union Army enters Chattanooga, Tennessee. |
| 102673 | September 9 | Event | 1886 – The Berne Convention for the Protection of Literary and Artistic Works is finalized. |
| 102674 | September 9 | Event | 1892 – Amalthea, third moon of Jupiter is discovered by Edward Emerson Barnard. |
| 102675 | September 9 | Event | 1914 – World War I: The creation of the Canadian Automobile Machine Gun Brigade, the first fully mechanized unit in the British Army. |
| 102676 | September 9 | Event | 1916 – Piggly Wiggly, the first true self-service grocery store, is founded in Memphis, Tennessee. |