Hi,
The modules are display directly by Joomla ; HikaShop provides a module which allow to display listing or product or listing of categories.
That module is perfectly working fine ; even our demo website have a category listing module in the sidebar.
Now if you cannot add a module in your homepage ; you should see with the template or Joomla. But I don't think that your issue is related to the HikaShop module.
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.