Degree

The eligibility criteria of DMS IIT Madras for MBA course is Graduates (or professional qualification equivalent to that of a University degree recognised by the UGC) in any discipline with first class or 60% marks (55% for SC/ST/PD) earned in their degree from a recognised/reputed University. IIT Graduates who have obtained a CGPA of 8 and above on 10 are exempted from the CAT score. So your academic profile is good enough for DMS IIT Madras for MBA course. The expected CAT cutoff for DMS IIT Madras for MBA is above 98. Hence, you have to score above this.

Yes, you can study M.Tech CSE Cyber Security after B.Tech IT. The eligibility criteria of M.Tech CSE Cyber Security is B.E/ B.Tech Degree in CSE / ECE / EEE / EIE/IT, MCA M.Sc. In IT/CS, AMIE or other equivalent degree.

Yes, you can only start pursuing CFA if you are a graduate or in the last year of graduation. So, you can register yourself for CFA Level 1 once you are in 3rd year of BBA programme. CFA does provide a path-breaking career.