Have you an idea to test the cron job functionality indipendently from my url ?
If you have the echo command in /var/www/clients/client0/web9/bin, then you can e.g. use such a cronjob:
echo 'test' > /tmp/test
you should find a file called test then in the tmp folder of the website. You can also verify cron by using a URL cron as I suggested, if the value in your db gets incremented, then it works.