Unlike Southeast Asia, where vegetarian diets are quite commonplace, you will find that most Koreans are dedicated omnivores. Expect food options for vegans in ICN lounges to be limited at best; there will likely be *something*, at least a bread/pasta/rice based option, but secret meat ingredients are really commonplace in East Asian cuisines. You may want to plan ahead by reviewing restaurant options in the terminal if food is important to you on your layover.

But honestly, 9 hours is plenty of time to take a transit tour or get out into Seoul and visit. I’d strongly recommend doing that - it’s super easy and a fun place to explore, and the lounges will wear out their welcome by hour 2 or so of your layover.