In Germany, November 9 is loaded with a lot of different historic events. In 1918, the Weimar Republic was declared, ending the Kaiserreich. Kaiser Wilhelm II went into exile in the Netherlands. The first democracy was established. However due to several circumstances and design flaws, the Weimar Republic failed, culminating in Hitler taking power on January 30, 1933. We all know what came of that, the 12 worst years in German history.
On November 9, 1938, many Jewish facilities were molested or destroyed in one of the worst civil uproars, encouraged and instigated by the Nazi regime. These terrible acts of violence pathed the way for all the later events that would result in the killing of over six million Jewish people. Because now the Nazis knew that their year long efforts to paint Jewish people in a bad light and blame them for everything that had been going wrong with Germany in the past 20 years, had worked, and many in the general population were willing to accept what Hitler had planned.
And in 1989, a mistake in the form of reading out a press release one day too early about granting East German citizens the right to travel freely to West Germany, led to the Berlin wall coming down. This wall had separated West Germany, AKA the Federal Republic of Germany, from the GDR, the German Democratic Republic, AKA East Germany for over 28 years. This peaceful revolution, which had started much earlier than November 9, 1989, led to the reunification of German under the West German form of democracy on October 3, 1990. October 3 is now a national holiday.
There were many voices who wanted November 9 to become that holiday, but due to the many other historic events, of which at least one had such terrible consequences, it was decided to choose a more neutral date.