The bar at the California Grill is probably one of the hardest to get into. You would have to go to the desk on the 4th floor and see if there was room. There often isn't.
There are many bar/lounges in WDW where you can get appetizers/food and relax with an adult beverage.
The Tamu Lounge at the Poly can get crowded with guests waiting for 'OHana but it has appetizers and is agood choice.
The Crews Cup Lounge at the YC is really nice. It has a "clubby" feel and offers a limited menu from the Yachtsmans Steakhouse next door.
You can order a drink and food in the Tune In Lounge at the 50's Prime Time Cafe.
There are many, many others and I am sure others will chime in.
Have a Great Trip