If you really are as good at your job as you say you are, I suggest you ask working women on r/twoXIndia to share their experiences with taking a break in their career and bouncing back. I am not in favour of letting them know your entire situation, because I do think the sub is quite overcautious but their experiences wading the corporate world will help.
As for financial freedom, leaving your IT career might entail that you let go of your independence, but being aware of the semi-rural joint family-homemaker dynamic, I don't think this in any way should be conflated with "losing independence." Working in his business would mean you get your own money, not working in it will also mean you get your own money from him while chilling at home. That's how I've seen it happen in my family & relatives. You need to figure out if you'd like that though. Maybe also work out what compensation you'd require to get comfortable leaving your job and being dependent on him, considering you both consider this route too taxing for you.
Apart from that, I think it would be a big ask for you to expect him to leave his family just because you're marrying now. These are people who he grew up around, who have loved him. They may have some archaic ideas but, I don't think they would want to overtly restrict you either. What is his opinion of this folks?
If you think he can stand up for you and mediate well in case of disagreements with them, he'd still be a green flag. You'd be expected to adjust in the beginning. You can ofc like he suggested, move out eventually.
If they're letting him marry out of love without drama, they're probably nothing extraordinarily extreme. You have a high chance of encountering the usual Indian-toxic in every new relationship/AM set up too. No one can give you a roadmap of the marriage before it begins.
You've been with him 9 years, evaluate how he has been towards you and decide based on that. Do you have compatibility of thought? What type of women are his mum and other relatives? How have they raised his sister/female cousins?