Self soothing

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Anyone have advice on how to get my son to self soothe? He turned 9 months yesterday and during the day he will not sleep unless I am holding him. He sleeps good at night but it has to be dark, music on and rocked to sleep. I have tried putting a blanket over his window so it is dark like at night but nothing works. He just screams and screams. I go in every 5ish minutes and soothe him and lay him back down but then he just screams. I have also tried laying him down and putting my hand on him for comfort until he is asleep or drowsy enough but as soon as I walk away he is awake again. The weighted sleepers don’t help either. Idk what else to do