Crib sleeping

Hi, my is going to be 9 month in weeks time. We had started making him sleep in crib but one side was open towards our bed. Now he is crawling a lot and started to stand by holding things. So we placed the other side of the crib as well and put the mattress on the lowest but he wakes up in night a lot and start to crawl or sit. How with all side closed how do I manage to go back to sleep as I use to tap him now and his him which seems issue now. Also I have crib protectors but he still hits his head on the crib side as they aren’t fully covered until top. Please suggest what can I do for both cases.