I have the strategy guide, here's their strategy for 9-3.

Use ranged units with large area attack abilities, of any element. Shiva is a good Rank III esper. Kytes is good with Blizzaga. Use a good balanced unit mix. Take control of both summon gates, then move to the sport in front of Feolthanos, finish them. Good luck!

After trying that strategy, I request that you watch this video please...
YouTube - Star Wars Kid: Remix