Series was licensed, first volume to be released by Yen Press in April 2015.
Baka_tsuki has deleted the LN from their lists.
Psylocke Scans has done Volume 3 but seems to have stopped.

If anyone else was looking for the source or even proof, it took a bit of doing but here you go. 😀

https://www.hachettebookgroup.biz/titles/satoshi-wagahara/the-devil-is-a-part-timer-vol-1/9780316383127/