You are not alone. This is a bug in libevent, but it seems the debian package on raspberry pi doesn't have the fix.
Other people already reported it:
* https://github.com/litecoin-project/litecoin/issues/351
* https://bitcointalksearch.org/topic/bitcoind-starts-at-reboot-but-rpc-calls-wont-work-2345585 (that crontab fix is ... well ... kinda shitty).
* .. and a lot of other links I already closed.
Try this, in /etc/systemd/system/bitcoind.service:
[Unit]
Description=Bitcoin daemon
After=multi-user.target
Instead of "After=network.target", use "After=multi-user.target". It will start the service after the boot sequence. Not sure it will work on your raspberry pi, but it worked on mine:
root@r01:/home/mycroft# netstat -nap|grep bitcoind|grep LISTEN
tcp 0 0 127.0.0.1:29000 0.0.0.0:* LISTEN 706/bitcoind
tcp 0 0 127.0.0.1:18332 0.0.0.0:* LISTEN 706/bitcoind
tcp 0 0 0.0.0.0:18333 0.0.0.0:* LISTEN 706/bitcoind
tcp6 0 0 ::1:18332 :::* LISTEN 706/bitcoind
tcp6 0 0 :::18333 :::* LISTEN 706/bitcoind
AWESOME! That did it! Thanks for helping me out