Amusingly, over the last few years, that question has *never* been asked. We've actually thought about putting an option in to disable those social buttons but, without it being requested, we generally don't add features just for the heck of it. Less to maintain and less for users to configure.
So, no, we don't have an option for it. However, it should be a pretty easy thing to hide, if you're ok with adding a little bit of CSS to your template. First, you'll need the SCLogin module instance ID. When you're in the module manager, this is simply the ID column, like "93". Once you have that, add the following to your template file (or any CSS file that loads on your home/coming soon page):
#sclogin-93 .sclogin-social-login {
display: none;
}
That should be all you need to hide it.
I hope that helps, but if you have any other questions, just let me know!
Thanks,
Alex