I would put him down for the night later, no problem at all with a 9:30-10 pm bedtime. My son was in daycare from the time he was 9 weeks old. The infants had as many naps as they needed (or their parents requested) until they were a year old. My son slept on his own schedule (slept when tired, ate when hungry, changed when wet) until then. He took at least 2 daytime naps. We did put him down for the night when we went to bed which is when he had his last feeding. Actually, it was more like we stayed awake until 11 pm or so until he had his last feeding and then we went to bed.
My son transitioned to one nap at 12 months of age in daycare and it was PAINFUL. He was exhausted for weeks. I would not take away any sleep at all that your son wants. He is only 7 months of age. Taking only one nap a day seems pretty unusual (most babies drop to two naps from 3 at about 6 months) but he is getting plenty of night time sleep.
From webmd.com:
4-12 Months Old: 14 - 15 hours per day
While up to 15 hours is ideal, most infants up to 11 months old get only about 12 hours of sleep. Establishing healthy sleep habits is a primary goal during this period, as your baby is now much more social, and his sleep patterns are more adult-like.
Babies typically have three naps and drop to two at around 6 months old, at which time (or earlier) they are physically capable of sleeping through the night. Establishing regular naps generally happens at the latter part of this time frame, as the biological rhythms mature. The midmorning nap usually starts at 9 a.m. and lasts about an hour. The early afternoon nap starts between noon and 2 p.m. and lasts an hour or two. And the late afternoon nap may start from 3 to 5 p.m. and is variable in duration.
Also - you WANT him to know that if he cries, you will come get him. That is how babies develop confidence in you and then self confidence. How else would one expect them to communicate at this age? You don't need sleep training, your baby is doing amazingly well sleeping. Just enjoy.