MS/MBA after working on H1B Visa and coming on F Visa

Hi All, I am B.E (Electronics and Telecomm) having 9 yrs work experience and working in US on H1B and I am already staying there for 4 yrs . But I am planning to do MBA/MS from US University… So If I come on start on Student visa. After the college completion will my future employer file a new fresh H1B visa or can continue on the existing H1B. Or should I go for OPT first.