I have never soaked any beans that I cook and when cooking the beans in the slow cooker it takes around 8 hours to fully cook the beans and make them soft enough to eat.
It can also depend on the type of beans you're cooking as some beans I buy take longer than other beans to fully cook and become soft enough to eat.
Cooking the beans on the stove can take around 6 to 8 hours as well depending on the type of beans you're cooking.
Soaking the beans is supposed to make the beans less gassy and also help them cook a bit faster but not much faster.
I just put the beans in the slow cooker while I'm away at work and when I come home the beans are cooked and ready to eat within 8 hours and I've never soaked them beforehand but you can do so if you want too.