It is not uncommon for infants of this age to change their sleeping habits.
If he is waking up, and not hungary, and not crying, then leave him be. Most likely he is practicing some new milestone, and is so intent on learning that sleep has taken a backseat.
When mine where this age, they would wake, and as long as they were playing in their crib we would leave them alone. When they tired they would lay back down and go to sleep on their on.
Set up a regular bed time routine, (warm bath, story book, and rocking if you have a rocking chair, some classical music),put him in his crib and leave the room. Do not go back in till morning unless he is crying.
There is one exception to the crying. If he cries when you put him down and leave the room. this is another issue entirely, and if this is the case email me and I will be glad to advise on that.