Yes it's on the dialer, but I missed having the icon on my home page. You can download an AT&T voicemail app from the store.
Thanks for this tip. Didn't know I could do this in nova.You can get it, at least on Nova launcher (and perhaps other launchers too).
In Nova, add a new widget, then in the Nova Launcher section, choose "Activities".
In "Activities", scroll all the way down to "Visual Voicemail", and choose the last option "Visual Voicemail - .ui.VVMActivity". That will turn your new widget into a shortcut for Visual Voicemail.
Works for my AT&T S8+, hopefully it works for you too.