See zOMG wiki page Leveling Guide.
Otami Ruins Mask farming works up to 8.7. Hive World is great for orbs and rings to salvage.
If you can find a Shallow Sea crew willing to go at your CL this is the best way to level up! Be careful Shallow Sea can be very dangerous you should be about 8.6 or higher.
Shallow Sea farming will be your main source. Hive World is fun at any CL, just make sure your crew is all green to you. If you can find someone with the quest farming the Gauntlet in Otami Ruins is great fun! Or reduce your power to go back to any earlier area and do repeat quests. There is also Deadmans Shadow, a new place for people to level up past CL 10.