Putting baby to bed


So, I try to not let my baby nap after 6:30. We wake up for the day around 8 or 9 and he takes about 2-3 naps a day. We do baths every other day around 8:30 and then I feed him but then he just won't go to bed. Any tips? His diaper is clean and he is fed so is he just not wanting to sleep? Or could he be over tired and we need to start this routine earlier? He is 9 weeks old