2 of mine didn't roll at all, and one didn't roll back to front until he was nearly 10 months! He could actually crawl before he could roll! My point being that you can't really set goals for them to achieve by a certain age as they do all do things differently and often in different orders - ds has always had much better fine motor skills and little interest in gross motor which means that he has often looked "behind" because he is not as interested in practicing gross motor skills.
I would say that rather than looking for him mastering a particular skill you would be better to look at the overall picture - is he contented, is he responding to you, is he interested in the world around him? Those things are more significant - and noticeably absent in a baby who is genuinely not thriving - than whether or not he can do something that "other babies his age" can do. It is also entirely possible, if he is on the small side, that he is going to take longer to develop the musculature that means he can do these things - that doesn't mean that there is anything wrong.
What I'm trying to get at is that everything else you say suggests to me that he is doing okay with feeding - good latch, good supply, plenty of wet and dirty nappies - and I am concerned that you are worrying unnecessarily simply because he is small. Some babies have to be - that's how the charts have to work, with some at the top and some at the bottom. In my experience there are a lot of health professionals who feel that they have to intervene with small babies and there isn't always a reason to do so. Try to trust your instincts on how he is doing, and don't assume that bf'ing isn't working just because he is small.
At 9 weeks my first thought for the fussiness and the NWs would be OT - they need so much sleep, and when you don't have time to resettle because of the older one they fall into an OT loop really quickly. It is also very easy to assume that they are hungry when they wake up tired because they do give a lot of hungry cues. Are you able to put him down for his naps a bit earlier to see if that will help him sleep longer? Another thing you could try is holding him through the jolts - it's not something that I ever did, but I think there is a sticky on it over on the sleep board.
Last point: if you are hating bf'ing, and it is making you stressed and you don't believe that it is working for your lo then don't feel that you have to continue - a happy healthy mum and a happy healthy baby are much more important than sticking to something that isn't working because you feel you have to.