Updated: Jun 1, 2021
As indicated in the datasheet of the controller (9800) no licenses are required to boot up a Cisco Catalyst 9800 Series Wireless Controller.
However, in order to connect any access points to the controller, Cisco DNA software subscriptions are required. To be able to connect to a Cisco Catalyst 9800 Series controller, each access point requires a Cisco DNA subscription license (AIR-DNA). After the expiration of the DNA subscription licenses the perpetual network stack will still be available and the APs will continue to work registered on the corresponding controller. If going to connect an AP to another 9800 then a DNA license will be needed.