Video cards just hot, many time hotter than a CPU. I've had 2 cards in crossfire before and actually burned my hand taking the top card out one time.
90C is 194F, think of it that way. It is not uncommon for a GPU to hit 90C and that heat gets transferred to the cooler and the rest of the card. If you take it out immediately it is going to be toasty hot.
If your card is not actually having issues, I wouldn't worry about it. When cards get to hot they usually start to display artifacts in games or crash the display drivers.