Why is September the 9th month based of the name it would make more sense for it to be the 7th?

The Romans originally only had 10 months in a year,with September - 7th month - being the 7th.

After the death of Julius Caesar,a new month was added in his honour,and as the Romans wanted his month to be a sunny one with fine weather,they put it in the Summer and called it July.

After Augustus died,the Romans did the same for him,and put his month - August - in the Summer for the same reasons.

This bumped September up to month 9,where it remains today in the Western calendar.

Edit:

The Roman year began in January - named for the god Janus,who had 2 faces - one looking back into the year just finished,and one looking forward to the year just beginning.

Our Calendar is based upon the Roman, and that calendar had March as it's first month. July used to be Quintilis, August was Sextilis.

And in modern use, September (Septembris), October (Octobris), November (Novembris) and December (Decembris) still retain their original names based upon being the 7th, 8th, 9th, and 10th months in the year.

It used to be. Under the old Roman calendar there were 10 months to a year and September was the 7th month, Oct 8th, Nov 9th, Dec 10th. Julius Caesar changed it.

http://en.wikipedia.org/wiki/Julian_calendar

The Roman year began at the spring solstice, in March,and this custom actually continued in Western Europe until around 1750.