Hello Aspirant, To get rank under 10000 in kcet you should score  at least 70-80 marks in the examination .As your expected marks in 12th will  be 90+ then , your rank will be given on the basis of inter marks and kcet marks .

The total number of seats available for each course at the institution. The difficulty level of the question paper. At least, you need to get 70% to get the rank below 10000 . According to the review from the KCET , it is observed that the cutoff for the general category is supposed to be 50% of the total marks.

Good luck !