delay.py

import sys
import xbmc
import time
import requests

def http_get(url):
    r = requests.get(url)
    if r.status_code != requests.codes.ok:
        xbmc.log('ERROR - %s') % r.text
        r.raise_for_status()

def amp_on():
    url = r'http://10.0.0.9/cgi-bin/relay.cgi?on'
    http_get(url)

def amp_off():
    start = time.time()
    while time.time() - start < 60: # seconds
        xbmc.sleep(1000)
    if not xbmc.Player().isPlaying():
        url = r'http://10.0.0.9/cgi-bin/relay.cgi?off'
        http_get(url)

if __name__ == '__main__':
    # use argument 'start' for onPlaybackStarted and 'end' for onPlaybackEnded
    if sys.argv[1] == 'start':
        amp_on()
    else:
        amp_off()