I found the solution! It works with the init script:
/etc/systemd/system/multi-user.target.wants/hyperion.service
[Unit]
Description = hyperion
After = mediacenter.service
[Service]
User = osmc
Group = osmc
Type = simple
ExecStart= /usr/bin/hyperiond /etc/hyperion.config.json
Restart = always
RestartSec = 1
[Install]
WantedBy = multi-user.target