Did you use a level boost, a story boost, or both? EVERYTHING is locked behind some amount of main scenario quest (MSQ) progress so just spamming dungeons to hit 90 ASAP is pointless.

If you have a main scenario quest (MSQ) active, go do it, and keep doing the MSQ til you're done. If you don't have a main scenario quest active, there should be a thing on your screen telling you where the next quest is.