Buying a crib for a 21 month old or straight to toddler bed?

Me and my husband are getting custody of his 21 month old son permanently and I’m trying to decide between getting a crib or toddler bed he’ll be sharing a room with our baby who is 9 months old and I’m trying to figure out what would be best he isn’t used to bed times or staying in bed or really sleeping in a room on his own so a toddler bed feels dangerous for both babies but a crib feels dangerous in the way of I’m not sure if he’ll try to climb out and hurt himself