Have you tried running the script directly on your odroid to see if it outputs anything relevant?

You're calling sudo with no interaction. does sudo require a password on your odroid?

If you've started pd and jackd with the same user that runs this script you shouldn't have to call sudo. There is also a way to allow the user to call 'poweroff' but I forget how you set that up.. it might be a group that you have to be in.