Hi all,
This topic should be tagged as osmc or similar so OSMC https://osmc.tv users can benefit from pihole too.
First of all: I had to execute this to finish the installation.
[SOLVED] -bash: pihole: command not found - #5 by piehole
Also it is necessary to change pihole default web admin interface port inside /etc/lighttpd/lighttpd.conf
to something like 8088, so it does not interfere with Kodi's web UI.
I have also disabled pihole's dhcpcd as it interferes with connman too:
sudo systemctl disable dhcpcd
To pihole devs: guys, can you pls. consider update of your great tool so it does not require that necessary portion of magic as above? 
Thx in advance!
Cheers!