Is it possible that I can take the SAT to apply to the universities in the US after my IGCSE O-Level (10th Grade) exams?
Yes - literally anyone can sign up to take the SAT. No particular SAT score will guarantee you admission to US universities, nor is the SAT necessary to apply to college. Some selective colleges require SAT or ACT scores for admission, many will consider them as an optional component of your application, and many don’t care for SAT scores at all.
That said, some universities will not consider you for admission without A-levels or equivalent, but many of the less selective universities will. If you cannot find a list of admission requirements by country on a college’s admission website for international applicants, you can email the admissions office and ask.
I would like to point out that it is not easy to study in the US below age 18 if your parents don’t live nearby. You wouldn’t be able to sign any sort of contract yourself, from opening a US bank account to participating in college sports or even just seeing a doctor.
How old are you?
Can you be full pay?
What IGCSE would you be taking and what are your predicted grades?
Some public universities admit students with only IGCSE 's and Sat scores. Some are relatively high ranked, such as Penn State, but expect you to be at least 17 when you enroll.