hello sudarshan,

90 marks in KCET is a good score and with this 97 % in boards will prove to be a rank booster for you so i think you'll be able to fetch a descent rank with this but rank are something we ca't be sure about before the actual result is out as they may depends upon various factors like number of applicants fill the form, number of applicants finally appeared in the exam, number of questions asked in the exam, difficulty level of the exam, performance of the candidate, previous year's cut offs trends but you may check your rank (predicted rank) with the help of career 360 KCET rank predictor and even have a look on what colleges you may get with that rank by the help of our KCET college predictor I am providing you the link for both. 

https://engineering.careers360.com/kcet-rank-predictor

https://engineering.careers360.com/kcet-college-predictor

hope it helps:)