I really don’t get it

Sleep is my nemesis. How is it that babies are recommended to sleep 9 hours every night but then you are supposed to put them down at 7pm and they wake at 7am? That's not 9 hours.

My issue: my son is 7 months old, he will go down at 7pm and wake at 7am with a few wake ups at night for like 10-30 seconds then back to sleep. He refuses to nap. Naps are 1-2 times a day for 10-20 mins each. At 4 month appt pediatricians not worried. We have put 6 month appt coming up so I'll check back in but I'm so confused. I'd like him to nap longer during the day. He goes to day care and also refuses to eat all day while he is there. So barely any sleep and barely any nutrition from 9am-5pm. If I wake him up earlier will he nap better? All of the sleep schedules online are like 12-16 hours of sleep a day and it doesn't make any sense