@HK2LS  Hello, 

Powerline adapters transmit data through powerline grid in the house, ordinary adapters use live line and neutral line to transmit data, with MIMO technology adapters transmit data through live line, neutral line and ground line, which larger the throughput between 2 powerline units.

PA9020P KIT is wired powerline KIT and does not have WIFI on the 2 units, if the model begins with " WPA", that  has a wireless part,

WIFi could be disabled for wireless power line unit, tpPLC Utility could customize wireless settings for powerline units. 
https://www.tp-link.com/support/download/tl-pa9020/#Utility

Here is an FAQ to change a WIFI name and password for WiFi powerline unit:
http://www.tp-link.com/en/faq-1611.html

Hope this could help~