If a restaurant asks for biz casual, then why not just make it easier on them and everyone you're dining around and dress appropriately.
Just because it's near a theme park, doesn't mean folks get to walk in somewhere looking like they just woke up. Orlando has tons of places to buy a preppy looking Polo shirt... It's not rocket science.
Trust me: You'll look better, you won't stick out like a sore thumb and, frankly, it's what Emeril's asked for in the first place.