Hi,
Regarding your request "without VLAN"... Each interface must be in some VLAN. By default it is VLAN 1. This VLAN is not marked with any tag and therefore you can connect it to any device.
And yes it is possible. But not recommended. If each SSID has different password then it is like you have more keys (passwords) for one lock (one VLAN).
On WLC it is simply to configure. Just set same interface for each WLAN in WLAN configuration.
On autonomous AP it is possible only over CLI.
GUI doesn´t allow you to create more SSID in one VLAN.
