The Church of Scientology organization is hierarchical -- there are no recognized autonomous congregations, by design. However, considering that the Church considers anyone who has taken a Scientology or Dianetics self-improvement class to be a Scientologist, only a minority of the official membership is actually actively involved in a Scientology group or organization. And quite a few more consider themselves Scientologists but do not check in regularly. So you could say their organization is hierarchical but their membership is mostly autonomous.
Buddhism is autonomous because there is no central authority.
Autonomous. Judaism today does not have a hierarchy, except on a very small scale within each independent synagogue.
Scientology is Fake.
You have to take a class for Scientology.
There are over 11'000 Scientology churches, missions and groups worldwide. To find the closest one to you, you can use the "Scientology church locator" on the Scientology website. That is a map that shows you the location of all Scientology churches and missions.
The Scandal of Scientology
Scientology was invented by the author Ron Hubbard.
Scientology cross was created in 1955.
The Scandal of Scientology was created in 1971.
Scientology is international. The Scientology religion has over 11,000 churches, missions and groups all over the world.
The Bahá'í Faith has a hierarchical administration: elected groups of people, one at the international level (the "Universal House of Justice"), one for every country, or in some cases other kinds of regions (currently called the "National Spiritual Assemblies"), and one in each city or town where there are 9 or more believers (the "Local Spiritual Assemblies"). I am not sure what you mean by "autonomous". The Bahá'í Faith is certainly not a branch of another religion; in this sense, it is independent, with its own laws, its own administration, etc.
The Scandal of Scientology has 220 pages.