can one apply in ISB Bangalore after declaration of CAT results?

ISB only accepts GMAT scores. You can refer the eligibility criteria as shared below :

PGP

Bachelors degree or equivalent in any discipline
Valid GMAT / GRE score at least 24 months of full time work experience by
March 31, 2018TOEFL / IELTS / PTE score (only if the language of instruction at undergraduate study level isn't English)


Early Entry Option (PGP deferred)
To apply under the Early Entry Option for a deferred admission, you will need to have:

Bachelors degree or equivalent in any discipline
ValidGMAT /GRE scoreLess than 24 months of full time work experience by March 31, 2018TOEFL / IELTS / PTE score (only if the language of instruction at undergraduate study level isn't English)