Can we locate kitchen room over the house septic tank?

I'm not a plumber but I'll risk an educated guess here and say absolutely not.

NO NO NO . What will you to if it needs service?

Sure you can! However you must leave holes in the kitchen floor over the inspection ports so the tank can be serviced. Gas masks should be provided for the occupants of the house to prevent inhaling the sewer gas that the tank produces. And. Oh yes. I would increase the health insurance on all family members including the family dog.
Now you can answer one of my questions. Why in the world would you even consider such a move? Cheers, Tom

Id give you 1/2 a greenie if I could!