At his age many babies don't eat a lot of solids & it's really only about taste & not filling him up. Milk is still the major source of nutrients, so yes filling him up in the day on milk is most important. Although by 6 months & more many babies can take a full feed in 5mins (sometimes even 3mins) & so even though it doesn't feel like they might be taking much they can be taking quite a lot & the night feeds could be more about comfort as they are for food.
Looking at your example above you've got him having 3.5hours day sleep & 12.5 hours at night which is 16hours total, which is A LOT for a 8mo (it's more about average for 3mo).
It may be that he's got a messed up Circadium rhythm. The most natural rhythm for humans is around dawn to dusk & I'm guessing that sleeping until 10am may be due to the disrupted sleep & the being tired & cranky at 9.30 could be less about how much time he's been awake in the day but that naturally, the body reacts to dark by being tired. Depending on how long the night wakings are they are robbing from day "awake" & the feeding has become a habit. I wonder if you were to shift his wake up to about 8am and then have his naps the same sort of timing as you've got, but try & get a bit longer awake time in the evening.
Also if you are finding he is waking a lot & the only way possible to settle him is by breast feeding it could be that he has fluid build up in his ears & him lying down at night brings about pain. My DS1 had fluid build up (but no sign of ear infections ) & it disrupted his sleep. Also babies who are mouth breathers can wake up more too, so it may not even be related to feeding or routine.