Hi leinhard,
Please try the following modification to your script line:
$script ="install all kickstart bootflash:n3000-uk9-kickstart.6.0.2.U3.0.709.bin system bootflash:n3000-uk9.6.0.2.U3.0.709.bin${CRLF}yes${CRLF}" <--- will be this command executed
If that doesn't work for your device enable session traces in NCM Advanced settings and send us the session trace log.
Regards,
Denys.