The SAT Subject Tests are optional, and students can choose to take them in any subjects that they are interested in. There are 20 different SAT Subject Tests, including tests in mathematics, science, social studies, and languages.
The SAT Reasoning Test is offered seven times a year in the United States, and it is also offered internationally. The SAT Subject Tests are offered six times a year in the United States, and they are also offered internationally.
So, to answer your question, there is not a different SAT test for each grade. However, there are two different types of SAT tests, and students can choose to take the optional SAT Subject Tests in any subjects that they are interested in.