Your icons are indexed in the search results shortly after submission. The process is automated, so you will just check again at a later time. If your icons are properly tagged, they will begin appearing in searches based on the specific tags.
Newly updated icons might not be easily discoverable because they are recently added. This means that a good practice is to promote your new icons on your own channels, in order to make them more discoverable for customers and start getting downloads.
Newly updated icons are not categorised immediately upon submission. This, however, is a manual process. It is just a matter of time for them to be assigned to a category.