Hi,
You can install HikaShop on a debug server without any problem.
The website where the license is attached is for the services we provide (updates, cron, support, etc).
If your website do not have a public url it is not a problem but you could use the the Joomla auto-updater for HikaShop and we couldn't provide the cron service.
Regards,
Jerome - Obsidev.com
HikaMarket & HikaSerial developer / HikaShop core dev team.
Also helping the HikaShop support team when having some time or couldn't sleep.
By the way, do not send me private message, use the "contact us" form instead.