Hello,
If you use latest theme version and all your plugins are up-to-date + you have checked all the server requirements before the installation https://www.8theme.com/documentation/xstore/theme-installation/xstore-theme-requirements/ Theme Options should work fine. Yes, your problems can be caused by the cache, try to clear all cache and temporary disable it at all.
Also, your custom css code needs to be added in Theme Options > Styling > Custom css or in style.css file of child theme (do not edit style.css file of parent theme).
To explore your problems more deeply, we need to check your site, so contact us once you move your site to live server and we’ll help you in no time.
Regards