Hi Hun,
It's really tough when your hand is forced, but it is dangerous when LO's start to climb out of the cot
. He is very young to make the transition, DS was around a year older. A lot of parents put a baby gate on the door, so he can get up but not get out to come into your room etc, so that would be a good place to start. Apart form that, I would recommend a Gradual Withdrawal or Walk in Walk out, depending on which he responds better to. With GW, you could sit next to the bed to start with. Then the choice you have to make, is whether you use rapid return when he gets up or whether you just stick with a 'sleepy phrase' and wait it out until he gets bored and gets back into the bed himself. Having done both I would recommend the latter, as I just couldn't find the energy myself for 'rapid return' it's exhausting!
But again he is very young to get the message in comparison to a 2.5/3 year old you know
Another idea (if you still have the crib) would be to use one of these, if he would tolerate it:
https://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=6&cad=rja&uact=8&ved=0CDAQFjAF&url=http%3A%2F%2Fwww.babycribsafetynet.com%2F&ei=GuEWVcbACOiM7AaLz4C4Aw&usg=AFQjCNHwrioqcc7Ve2_xLiHLRJAfLqgcKwIt would enable you to keep him in his cot much longer.
Thoughts
Here's a image so you can see how they work
x.