Good luck!! If you've already had the job on contract for 9 months, this interview process is probably just a formality. They already know you can do the job. Just be yourself. You probably just think you rub people the wrong way. Try not to overthink it (easier said than done, I know) and try to relax and be yourself. Being yourself got you that contract and being yourself has you being considered for a permanent position. So, being yourself is a GOOD THING.

Let us know how it goes.