A.
had been credited with transforming English football by leading a campaign to remove caps on footballers' salaries,
The use of past perfect tense is not warranted.
B. has been
credited for transforming English football by leading a campaign to remove caps on footballers' salaries,
credit with is the correct usage
C.
was credited with transforming English football by leading a campaign to remove caps on footballers' salaries,
The use of was indicates that Jimmy Hill is no longer credit. We need present perfect tense here.
D.
had been
credited for transforming English football by leading a campaign to remove caps on footballers' salaries, has
use of had is incorrect ; credit with is the correct usage in this context.
E. has been credited with transforming English football by leading a campaign to remove caps on footballers' salaries,Grammatically correct. Conveys meaning without ambiguity.
Option E