Yes, irons are a no, no. I have read pro/con in regard to irons on RCCL's. I know on Carnival Triumph, they had a small laundry room where you could wash/dry/iron your clothes.
I would suggest as someone already has, you can purchase a can of wrinkle be gone, or something like that from Carol Wright, or a place like that. I take a can with me. I spray it on the garmet where the wrinkles are, then sort of pull each direction with the material,and the wrinkles will come out.