Testing here with the older jessie based emonSD-26Oct17 image and the latest emonpi update I was able to replicate the issue of the services not starting after a reboot and have fixed the issue by adding the relevant entries to the rc.local_jessieminimal:
https://github.com/openenergymonitor/emonpi/commit/ecf1ef301cf8633e3c0000f54efc138678407e3e
Apologies for not catching this issue sooner. Unfortunately users who have updated prior to this update will need to login via SSH and start service-runner manually to initiate the update process to then fix for subsequent updates. The command to do this once logged in is:
sudo servicectl start service-runner
then run emonpi update from the emoncms Administration menu.
Note: It can take 5 minutes for all the services to come online after a reboot on jessie. The new stretch image is a bit faster. This caught me out to start with as I thought none of the services where starting but they did all start up fine after a couple of minutes.