K.P.
Thank you to JC for clarifying that CIO doesn't mean closing the door and hoping for the best. It is a step-by-step process that does work and quite quickly!
At 10 months old there is no need for night feedings. He is likely waking and looking for comfort, not food. Make sure he has a full belly before putting him down and be prepared for several long nights.
It is heart-breaking, but CIO does work. Your son will be a happier baby in the long-run once he learns how to soothe himself! We did this with my son and now he sleeps about 10 hours a night and goes to bed drowsy, but not sleeping. We also found that letting him attach to a lovely really helped. He looks for "Joe" when he's ready for bed.
Good luck!