Hi R.,
I went back to work with my first baby when she was about 8 1/2 months old. She went to daycare two days a week and grandma's house one day a week. For the first three weeks of daycare, she didn't nap barely at all. It was a home daycare and there were only three kids, but she still needed time to adjust to things. She would sleep for 15 min and if she woke up and cried, the daycare provider got her and brought her down. After those three weeks, she adjusted and would go down for one nap around 11-1. When I picked her up at 4pm, she was very tired and always fell asleep in our 20 min car ride home. This daycare provider also felt one nap under her care...for all the kids...around the same time...was best. So, the car ride home naps continued probably until 15 months or so. On the days she wasn't at daycare, she napped about 1 hour in the morning and about 2 hours in the afternoon. At 18 months, she consistently switched to one nap a day in the 12-2 time frame.
I was a stay at home mom for this time frame with my second child. He did two naps a day from about 6 months to about 15 months, then switched to just one.
Give the daycare adjustment some time. It will likely get better.