Stuck memory card slot on nikon d90

The thing about super glue is it is a usually a very brittle glue and is easy to break if you try. The problem is certain Super Glue formulations like Gorilla Super Glue are tougher to break through force like this. If Nikon used a plastic that's not as accepting of Super Glue, this is going to be much easier. The problem comes in if the plastic is very accepting and creates a bond that will require damaging the camera's plastic components.

I am going to assume that your memory card door is glued shut since that's likely where the glue seeped in to begin with. What I would do is start the plastic somewhere you can begin to break the glue bond and then stick a very thin flathead screwdriver in the gap you made by starting to break the bond, and then twisting the screwdriver to break the super glue if it looks to be brittle enough. It will leave some marks on your camera, but this will at least free the memory card door for you to see how bad the damage is.

The memory card is another battle to begin with. You won't know how much damage is done to the camera without breaking the memory card door open. You may have lucked out and it stopped before it got to the memory card itself. Now if it somehow got under the SD card itself, that complicates things further. If it got under the actual SD card, you may want to take the camera to a professional to recover your memory card and have them evaluate how much damage was done to the camera.

As to the camera... The best thing you can do is to try and save the camera, but I wouldn't sweat it too much if it has to be destroyed to recover your SD card. This camera is old enough that used examples with reasonable actuation counts are probably not hard to find. The other reason is you can replace the camera body itself, but you can't replace the data on the SD card itself. Once you get the card out of the camera, I would also recommend buying a new memory card as well. Copy the contents of this card to your new one and stop using the card that was glued into the camera. It will likely be damaged and will never fit in anything correctly again.