Omnis Software has touted WCAG compatibility as an upcoming feature. Their goal, as was shared at a conference in Boston in March, is to ensure Omnis fully compatible with screen readers and current and upcoming laws for regarding accessibility.
Studio 9 includes these features and is in beta now, with a release expected later this year. If your potential employer has a membership with the Omnis developer partner program (ODPP) then you could sign up for the beta and give it a try.
I don’t know how much the IDE has been changed to support screen readers, but I expect the free-form method editor that’s new in Studio 9 would be easier for a reader to navigate.
I hope this helps!