actually the Commentary gives the attainment of jhanas as one of the possible things that Bahiya might have attained , but doesc not state that he had definitely attained them.
it also says that he
had first heard the Dhamma a hundred thousand kalpas in the past under the
Buddha, Padumuttara and in that life had performed great meritorious
deeds. He had later gone forth’ under Buddha Kassapa .http://groups.yahoo.com/group/dhammastu ... sage/24977
Even so, in the present life, when he became highly respected by people
after he was shipwrecked and wandered around with only garments made from
bark, he mistakenly assumed he was an arahant because he was treated as
one. In fact he had not achieved any level of attainment at all and was
completely misguided, deceiving those who supported him and paid him
respect. It took a visit by Grat Brahma, a former deva companion and an
anagami (non-returner)who took pity on him, to shock him to his senses.
Great Brahma tells him: “You now, though being no arahant, roam about
wearing the guise of a religious in the belief that you are an arahant.
You Bahiya are certainly no arahant. Renounce this evil resorting to views