If a learner successfully completes any of the levels (9093), are they still required to sit IELTS for University entry?

IELTS is a separate qualification and not necessary towards completing an AS or A Level, neither does it count towards completion of such. IELTS is an English Second Language qualification, whereas 9093 is a First Language English qualification. It may be that certain institutions (e.g. universities) require one or both of these qualifications; this will be decided by each institution rather than by Cambridge.