I live in St. Louis. Downtown/Stadium is 7-8 miles from Ferguson. Just about everything going on there is isolated to that area and shouldn’t be a problem for you. I live 4 miles south of Ferguson in a mixed neighborhood.... there are no issues at all here, people are just going about their business.
It is mostly out-of-town rabble-rousers coming in.
You’ll be absolutely fine where you will be staying.
Hope you see some Cardinal wins!!