So night weaning is very necessary in your case. I assume when you say 4 bottles a day, that is 4 in the daytime plus 2 at night (rather than 4 in 24h, 50% of which is at night). The night feeds will be affecting his willingness to wean onto solids. By 9 months the shift wants to start happening whereby calories from food overtakes calories from milk - so that by 12 months milk is a small part of his diet, rather than the bulk of it.
That said - you have a chicken and egg situation with calories. He has night feeds so doesn't need as many calories in the daytime. But because he doesn't have enough calories in the daytime he is hungry at night - so the cycle continues. Breaking the cycle will be hard because of having to not feed a baby who is hungry. But being hungry for a few hours as baby gets older isn't a terrible thing, it's a natural normal feeling so don't beat yourself up over it.
By not feeding at night though, baby will be much more hungry in the morning and for the rest of the daytime. So shifting all calories into daytime hours will be done quite quickly, within 2 or 3 days (assuming you go cold turkey rather than drawing it out). Just make sure you add in an extra two bottles into your daytime routine (by giving bottles closer together). Then work on reducing milk in place of solids once all calories are in the daytime.
All that said, it's only indirectly related to sleep. So onto the sleep issue...
Good quality sleep hygiene needs him to go into his cot awake and go to sleep in there. Every time. so same for bedtime, naptime and all night wakes.
He is going to cry doing this. The joy of the dummy or feeding to sleep is that it allows for comfort sucking and it is physically impossible to cry while simultaneously sucking. Without the ability to comfort suck baby will cry. No ifs or maybes about it, he will.
The key this is though, don't take that crying as a reason to assume baby doesn't need to sleep, won't sleep, infact it might not even be distress. The only way baby can communicate is crying and these cries are baby telling you he wants to go to sleep but is frustrated because he cant. So you teach him . Teaching out children is a big part of being a parent. So try and reframe any crying as merely communication that he's tired.
That said, you still need to comfort him, im not advocating leaving him to cry to sleep. Without feeding he no longer has the comfort of sucking. So replace that comforting with in-cot comforting. Pat him to sleep in the cot. He's going to cry, so dont assume crying is a sign it's not working. But keep going.
Be consistent. Same all the time, same every time, same every sleep time.