Certainly you could adapt it to be run by any one of the number of systems that does precisely this - start a process on boot and restart it if it fails - that exist for linux: monit, supervisord, init, upstart, launchd. However, advising you on setting any of those up is perhaps a bit more involved than we can get on the forum.
Plus, the unfortunate reality is that the Centos 6 boot system, upstart, is only used in centos 6 - in centos 7 they'll be using launchd instead (reference: http://unix.stackexchange.com/questions/118454/upstart-documentation-for-centos-6)
But honestly your unclean solution isn't such a bad one. Here's how I'd do it:
in /etc/rc.local (which is run at the end of every boot), just add the command to run the plugin. You'll probably want to both redirect the output to somewhere and run it in the background:
command > /var/log/f5_plugin_output 2>&1 &
This only runs once, but the plugin does not in my experience crash very often - are you seeing it crash on occasion?