E.C.
First, resolve to do what you are doing. It will be easier on your and on him. Kids sense stress - and indecision. They work it! Thankfully he takes a bottle easily!As babies grow, one has to expect 'trauma' - meaning crying, arching the back, etc. They have a will and life does not always go according to their will. Raising a child means helping them learn to control themselves in situations that don't go their way - one can't yell at the plumber for taking a few extra hours - one starts learning that early one, slowly, slowly. At 8 months, he can sleep through the night without nursing.
He has been trained to fall asleep nursing; now he needs to be trained to fall asleep without nursing. He is older, stronger willed, more determined than at birth. But we are the adults and so it is our job to lead.
You can do it.
To wean without pain, think of lengthening the times between nursings. So if he nursed at 7am-11-3-7pm-4am, cut out one nursing - that will give 8 hours between two of the nursings. Don't nurse then for 2 days. Then, cut out another nursing, so you have another 8 hour gap. Probably best to have someone else give him his bottle and leave the house, so if he is crying you don't have to hear it. If you are going to wean him, there is not point in standing there torturing him and yourself.