It's tricky when it comes to making babies sleep every night at the same time. I would say start by building up a regular routine so that baby will associate this routine to bedtime.
For example if you are aiming to get baby to sleep at 9pm, maybe his last milk feed will be around 8.15pm, followed by perhaps a warm wipe down, lights off, soft singing, patting etc. Keep doing the same routine every night. For me, I used to give him a warm wipe down only on his hands and legs, followed by kisses from me and his daddy all over his checks and forehead, then I will use a baby belly binder to bind his belly lightly (to keep him tummy warm as part of the routine), lights off and then soft singing, patting. I uses the tummy binder on him til now even when he's turning one soon LOL. Bought a bigger piece though hee.
Night feeds will just be a very quiet affair, feed, burp and change diaper if he poo, then put him back to cot to sleep, most of the time I seldom need to pat or sing and he'll auto sleep after night feed. Best is if you can only switch on the night light for night feeds so as to minimize bright lights which may make him feel more awake.
So routine is the key :-) make it something different from his daytime naps.