what extracurricular activities should you take if you want to take admission at standford and mit?

First, no one can tell you what ECs to pursue to get into these schools, especially since you do not have one, and secondly since you do not have a clear idea of what you are going to major in at these 3 very different schools.

Please read the entire response. Hopefully, by the end, you will see that your assumptions are incorrect.

You cannot pick a college, and then backfill the ECs into that college application to get you into that college.

You have to start with your personal passions. Then have them develop into interests and extracurriculars. If they align with what you study in HS great. If they don't keep developing them so you become a uniquely qualified candidate. Your passions, interests, tenacity, drive, determination, and enthusiasm will dictate what ECs you will be applying with. It's true that some ECs are just good ones like being the Editor of your HS Newspaper. But if you are a terrible writer and don't like English, well it's futile to think your teacher will allow you have that position and you will not be that good at it.

Most elite colleges like MIT Stanford and Yale use a rating system to rank your extracurriculars on your college application.

Some use a 1-5 scale others a 1-6 scale.

So let's say you these 7 ECs -

1.) Played Water Polo

2.) Played bassoon

3.) Competed in Science Fairs

4.) Editor of your school newspaper

5.) Served on your schools student council.

6.) Volunteered as a board member of your cities DEI Diversity Equity Inclusion committee

7.) Did research as an intern for a BIO MED company with dangerous pathogens.

Each of the schools would have you write a 1 or 2 sentence explanation of what you did for each EC and then give you a rating.

For instance if you were the Team Captain of your WP team and you were the best team in your State and won a title, you might get a 2 out of 6. 1 would be reserved for someone who was on an Olympic development program. For instance if you were the best Bassoon player in your State and played on the State Orchestra and won various soloist awards, again you might get a 2 with 1 being reserved for being a National best bassoon player.

In those 2 cases, you may want to support your EC with a video highlight tape of you playing WP and playing the bassoon. If you are good enough to play on their Division 1 Water Polo team, Stanford might recruit you. Not so much with Yale and MIT since they only have Club Teams that do not compete in the NCAA conferences either in D1, D2, or D3.

So once the application reviewers tally up your ECs, they give a rough score on your scorecard. So let's say you get a 3.0 out of 5, or 3.0 of 6. That's pretty good. EC's is only 1 category of things that the elite colleges take into consideration so along with ECs, you will get a rating for Academics (which is your Grades and the Course Rigor of your course and Test Scores (SAT, ACT, APs, IBs, SAT II subject tests) ((That's usually 1 category together), Recommendations, Interview, Intellectual Vitality or Curiosity, Essays, Honors and Awards.

At a school like Stanford, they mostly admit students that have a range of scores from 2+, 2, 2-,3+. Like I said it's really really hard to be a 1+, 1, 1- across all categories. Its does happen but keep in mind it's probably less than 5% of the admits. They might admit a 3- if they are recruited athletes or development candidates whose parents donated $8,000.000 to a building fund as well.

Yale uses a holistic method similar to Stanford while I believe that MIT gives more weight on academics, ECS, and intellectual talent. MIT and Caltech typically admit those with the highest standardized test scores and those who have taken many advanced STEM classes like Multi-variable Calculus, Physics C Magnetism, and have won various science awards like the INTEL award, etc.

Hope this gives you a better idea that it's not the quantity of ECS you do but the quality of ECs that matters. Also, it helps if the ECs you choose to commit to speak to or support your narrative as an academic or human being. Do not pick ECs because you think it will get you into the college. Pick an EC that you are passionate about because if you are passionate about something, you will also be good or great at it.

Also, there is no time frame for doing ECs like your assumption that you are in 9th grade so you need to have ECs. What I would say is more important is that you need to have passions and then the ECs will come to you.