Hey there!
I believe the answer to your question is 24.
If it's being reduced by 1/3, you are being left with 2/3, so we can take 2/3 of 9 and you get 6. Perimeter is adding up all the side lengths. Thus, we do 6 + 6 + 6 + 6, and that is 24.
Sorry for any confusion before, I didn't understand the problem before. Hope it helps! Have a great day, and sorry if it's late.