I had a variation of this problem when my DS started daycare at 5 months and then again when he started a new daycare at 9 months.
Licensing here requires that every child under 12 months must have a crib that's just for them. In the first center, most of the babies didn't sleep in the cribs -- they sat their empty and the teachers put the babies in infant seats and rocked and sang to them while they fell asleep. My son had a medical issues and an apnea monitor and needed to sleep flat so that wouldn't work for him, so instead they'd rock him in their arms and then transition him to the crib.
At 9 months DS had surgery and afterwards he was super clingy -- he literally would not sleep unless I was touching him -- I couldn't sneak out to the bathroom, or stretch or anything without waking him up. He also screamed at the sight of the crib. This calmed down a little before he started, but still combined with starting a new daycare it made me very nervous, but he did fine. At the end of the first day the teacher told me "by the way, he doesn't like the crib, so I borrowed a cot for him from the toddlers. Licensing says we have to have a crib, not use it. So they stored the cot under the crib and pulled it out at nap time, and a teacher would sit beside him and rub his back until he was out. If that didn't work they'd take a walk with the stroller and he'd conk out there and then they'd transfer him.
DS attended a total of 4 places before he gave up napping at 5. In none of them was he ever left to cry to sleep, and except for a few days when he was 4 they always got him to fall asleep. I think 3 things played a role -- one is that daycare was fun stimulating and exhausting so he was ready for the nap. The other is that it's hard to feel "abandoned in the hustle and bustle of the infant room, even if the teacher has to stop rubbing for a few minutes she's always close by talking softly to another child so it felt pretty safe, and finally I think that even very young kid know when something's a possibility and will cry for it. So while DS would have cried if I was there but asked someone else to put him down, he didn't cry if I wasn't there at all -- just like as a toddler if he knew there were cookies in the cupboard he'd whine for them, but if he knew that there weren't any he'd go on his merry way and not waste the energy to ask.