Scenario:

The Computer is unable to grab an IP address from the Native VLAN when connected wirelessly to the EAP9550.

Answer: Basically this is a limitation on the EAP9550. You can’t customize each SSID independently with tagging. You need to replace the EAP9550 with EAP300, EAP350 or EAP600. For the EAP300, EAP350 and EAP600 it gives the option to select which SSID you can tag.

See VLAN setting from the interface of the EAP-9550/300/350 below:

EAP-9550 has no option to remove tagging on the SSID with untagged VLAN frame. Once Virtual LAN is set to enabled on the interface, All SSIDs (regardless with untagged frame) will be associated with tagged VLAN frames from the wired network.

Here's the VLAN setting from the interface of EAP300. When enabling Virtual LAN, you also have the option to specify as to which SSID would be associated to tagged or untagged VLAN frame from the wired network.

Here is the VLAN Setting from the interface of EAP350. Different from the interface of above models. It did not mention enabling Virtual LAN but Isolation. This option enables 802.1Q for VLAN tagging. Enable isolation only with the SSID that will be associated to Tagged VLAN frames from the wired network.