Do a Google search for "Wifi to Ethernet Bridge"
There's a ton of products out there. T-Mobile won't recommend a specific one. I haven't used any, so I cannot recommend one. Though, I'm beginning to wonder if one of these things will work in my sister's situation where her husband wants the router upstairs (for gaming) and she has a home office downstairs without WiFi.
WDS Bridge doesn't work. After set up the bridge setting on the router, and even successful ping the hotspot, there is still no internet connection. I think T-mobile doesn't want to open this function.
To connect a wired device you need a "range extender". Most will work if they have an ethernet port. I use a Netgear WN300 but other faster ones also work.
First, you need a computer to setup the range extender. Use an ethernet cable to connect the PC to the ethernet port on the range extender. Login to the range extender and search for the T9 in the available networks. Use the extender mode of the range extender. Select the T9 and enter the password. Save the settings. This will then allow the ethernet port on the range extender to pass the DHCP addresses to the PC or any other wired device. In this case the ethernet extender is being used to emulate a wired connection and not being used as a wi-fi extender. You can even connect the ethernet port on the extender to a ethernet switch.