A 9th grader in the US need not decide on a college major or career path yet.
The most that is required is to make sure that course selection in high school does not close off paths to any particular college, college major, or career path. But someone who follows a reasonable high school college prep base curriculum like that described in FAQ: High School College Prep Base Curriculum (choosing more rigorous options based on academic strength and interest) should be fine.
Typical decision points:
- Early 12th grade: if applying to colleges where one has to apply to a major or division (more common with certain majors like nursing or engineering), the student has to select the desired major on the application.
- Frosh / soph in college: if undeclared and undecided, consider what majors are of possible interest and choose introductory courses to work toward all of those majors (to avoid being “behind” on any) and determine which is of interest.
- Soph year in college: typically required to declare major during this year.
Law school does not require any specific undergraduate major; admission is mostly dependent on LSAT and college GPA. Admission difficulty is highly correlated to law school ranking; top 14 overall or top in the state one wants to practice law in has the best job prospects.