Student or Learner
Miniister in the Prime Ministerís Department Datuk Seri Nazri Abd Aziz said Abdul Rahman Bakri (BN - Sabak Bernam), who was arrested for alleged graft, is still an MP unless proven guilty.
Should the phrase in bold be 'unless he is proven guilty'?
The subject has already been stated in the sentence, and it is not necessary to name the subject again later in the same sentence. It's implied and understood.
Saying "unless proven guilty" is understood to mean, "unless he is proven guilty" in this sentence, so your understanding of the meaning is 100% accurate. It's just a matter of shortening the sentence while maintaining its exact meaning.