How do you change/set a child's bed routine?

Just generic advice, twofold.

First, what you consider battling is considered a distraction, and fun, by him.

So build on the routine, for example: eat, watch TV show or play, change into PJ's , brush teeth, lie in bed, one story.

Important: When he climbs out, act bored and don't give him any exitement, fun, or other reward for climbing out of bed. Put him back in bed with little or no words or anger.

Second. Your kid is very smart. He is definitely smart enough to learn, VERY quickly, that daddy's rules do not apply in mommies home.

My daughter is nine months and had a bedtime of 8:30 but about a month ago we had some friends come and sty with us for a few days and we haven't been able to get her back into routine since. Sometimes she is still awake when i can barely keep my eyes open so i have been just putting her in her bed and letting her play until she falls out on her own at 8:30 ( there is nothing in her bed that shouldn't be ). Maybe talk to your sons dad and see if he can try using the same routine as you

You need to make a plan with his father. You and he need to come to an agreed bedtime for him and both stick to it. (apart from weekends and special occasions only.) His father is obviously trying to do the right thing and caring because he is sharing custody. Do some research on how many hours sleep your child needs for his age (probably about 10) and why it is important and why routine is important for children also then speak to the dad about it. The closer he sticks to a routine the better it is for all especially your son, he goes through enough upheaval every week.