When in the Bible people are living for hundreds of years, they are 365-day years as we have them. The 365 day calendars was invented and used by the ancient Egyptians, and not by other parts of the world until much later.
Hebrew years rotated around seasonal changes and the lunar cycle. If we chose to age with the lunar cycle, Adam would have lived to be approximately 77 years of age. (930 / 12 = 77.5)
It should say that Adam was taller than the average man right now (A lot taller), because there was more oxygen.
He would live to 930 because the less exposure to the Sun because of the layer of water above the Earth (Preventing X-Rays), and a better diet. . .
Assuming Adam existed, an overabundance of oxygen would have killed him. This question is rather strange though. If he existed when people claim the bible said the world started (10,000 years agoish) , then the oxygen content of the Earth would not be much different than it is today. If he existed when oxygen was significantly different, his existence would be an anachronism. That is, oxygen levels peaked 280 million years ago (1), while the first anatomically unique human is estimated to have arisen 200,000 years ago (2). With that being pointed out, however, let's say Adam existed when the oxygen content of the Earth was 9% higher (1) (hardly "way more") 280 million years ago. More oxygen is not necessarily better. Exposure to 100% oxygen over a certain period of time is actually very harmful and can lead to blindness and, eventually, death (3). If 100% oxygen can kill over a shorter period of time, Adam might have been killed by 30% oxygen over a longer period of time faster than he would have died in a normal and more modern atmospheric environment. So, no, a higher oxygen content of the atmosphere would not lengthen the lifespan of Adam to 930 years.
1: Peter Ward: Out of Thin Air: Dinosaurs, Birds, and Earth's Ancient Atmosphere
2: nsf.Gov - National Science Foundation (NSF) News - New Clues Add 40,000 Years to Age of Human Species - US National Science Foundation (NSF)