It is very possible that he is teething. My 9 month old has been up constantly the last few weeks and in the last 3 or 4 days both of his top two front teeth have popped out. Also, he might be getting ready to start crawling or standing or another new skill. My son is a mover, and he is usually sitting or standing by the time I get in to check him when he wakes at night. Half the time he isn't really even awake, but he is sitting up so I try to lay him back down and pat him to get him back to sleep. This works about 25% of the time. The rest of the time I rock him or nurse him back to sleep.
Something to think about, I remember with my first it seemed like he would NEVER sleep through the night. He was up every 2-3 hours until he was 14 months old. But, once we reached that point, and I weaned him, he has been a great sleeper. In hindsight, it wasn't so bad, and it seems like a very long time ago (he is 2 1/2). I have been reminding myself that a lot lately as I am pretty tired from getting up with #2. This is a phase and it will pass. Do what works for you to get the sleep you need. They are only little once. They need you, that is why they cry.
Good luck to you.
J.
SAHM to 2 1/2 year old Charlie and 9 month old Joey