I am surprised that Germany, that I consider a word power is not on this list of countries that owns nukes, I consider them as one of the world's most advanced countries, also I wonder what is the criteria for only 9 countries owning nukes. Although I don't support for every country to have nuclear weapons, it will be deverstating if a country decides to unleash it on their enemy nation. So far all the countries that owns nukes are behaving well, I hope that it will remain so far the sake of innocent citizens, they can iuse it to flex muscles to their enemies but I hope that none of them will have to use theirs.
Nazi Germany was one of the causes of World War I and was the country that launched World War II under Hitler's leadership. For that reason, after losing World War II, Germany was forced to sign a commitment with other powers such as Britain, the United States, France...that they would never produce or possess nuclear weapons and in return they would receive protection from the US through NATO.
Although they do not directly possess nuclear weapons, they participate in NATO's nuclear sharing program. The US deployed 15–20 B61 nuclear bombs at Büchel, Germany, and they were operated by the US Army and the German Air Force.
There is no criteria for a country to possess nuclear weapons, it all depends on their resources, that is why North Korea or Iran despite warnings from the United States or NATO still deploy nuclear programs.