How do elite US colleges evaluate a late academic pivot from Commerce to independent STEM

Hi everyone, I’m from India targeting and I'm schools like Stanford, MIT, and UPenn for a Computer Science/AI major, and I need advice on positioning a highly non-traditional profile.

I spent most of high school in the Commerce stream with very low, fluctuating and erratic internal transcripts (56% in 9th, 72% in 10th CBSE, 34% in 11th, and 67% in 12th Commerce). I have always loved machines and computers and wanted to enter the TECH field instead of entering finance. So, I made the unconventional choice to completely restart my final year. Therefore, I enrolled in an open schooling Board (NIOS) to independently self-study the entire Physics, Chemistry, and Math (PCM) curriculum. I am graduating my senior year which I am repeating in 2027 and I am targeting a score or 85%-90%+ .

Outside the classroom, my profile is driven by independent execution. I’ve launched two successful business ventures including a freelancing service yielding ₹10,000 (~$100 USD) profit and a graduation event that generated ₹1,72,000 (~$1,785 USD) in revenue and ₹30,000 (~$310 USD) net profit. I am also the former captain of a U-19 basketball team and am currently self-teaching programming to launch 1 or 2 polished projects on GitHub by mid-October.

Given my background, I have three quick questions:

1. What is the best way to frame a drastic academic pivot like this in the "Additional Information" section and the essays without sounding like I'm making excuses for my past grades?

2. Since I lack traditional school vouched STEM metrics (like olympiads or lab work), will a top-tier standardized test score and a working coding portfolio be enough to validate my academic capabilities for a CS major?

3. How should I guide my teachers when drafting my letters of recommendation to ensure they highlight my self-directed learning style and operational discipline?