Blueman is a very common bluetooth GUI for Linux. Ultimate Ears Bluetooth speakers can be remotely "turned on" by sending a special packet. This plugin allows you to do exactly that from Blueman's UI. It uses the MAC address of known devices to guess if a device is likely to be a UE speaker and only displays the "turn on" button when that's the case.

Inspect the contents of install.sh (there's one line to read ?) and run it. If it doesn't work, then re-read the script and try to understand what it does concretely, it shouldn't be hard to adapt to your system.
Creating a deb file might be nice too.
For some reason, on my PC, I can only turn the speaker on once per power cycle. After successfully powering the speaker on, I won't be able to send more packets until I reboot. Maybe there's a cache somewhere that I should clear, but I don't know precisely how the Bluex stack works and don't have the time to look into it.