@Deeppak I also live in India but I am an American expat.
I do understand that schooling in India causes parents a lot of stress because there are so many choices of curriculum. From my point of view, the first decision you want to make is will the child be studying in India or abroad after 12th. If the child is going to stay in India - you need a syllabus that will prepare them for the Indian boards. CBSE is a very good syllabus that is trying to modernize and meet the needs of students. The most important thing is the quality of the school and the teachers. If you have a good CBSE school in your town - you should stay with that school.
If you want to send your child abroad after 12th you have to take a different approach. While some very talented CBSE students are able to study abroad, it is a difficult challenge for them because college can be very challenged as the change in teaching and learning methods may be huge. That is why parents who know that their child will go to the US choose the IB syllabus or IGCSE. However, if you are in a small town these may not be available.
If you want to send your child abroad you must be prepared for the expense. You should be ready to spend close to $60,000 per year as a rough estimate. And a child from outside of the US has no guarantee for scholarships or financial aid. Therefore, unless you are a very wealthy family, it may be best to look at Indian colleges.
Apart from IITs there are other very good colleges in India now that are more like American liberal arts colleges. Schools like Ashoka outside of Delhi have a very good reputation for a well-rounded education.
Things that are important in India (like Olympiads) cary very little weight outside of India unless your child is a national topper.
You might also want to consider that there are very good colleges in Singapore and other locations a little closer to India. These options are also cheaper than the US.
Right now here is my suggestion:
Find out your son’s interests and aptitudes - help him discover those.
Put him in the best school you can find in your town - one that will help him reach his potential and be a well-rounded person.
When he gets to high school you will probably have to start considering what coaching to get him into. I recommend an integrated coaching-school program. My friends have kids in those integrated programs and it works out much easier for the child.
Remember - he is a child. Let him pursue arts, sports, music, theatre, drama or whatever he enjoys. He only has a childhood once.
Best of luck!