by 9 months, she'll be totally different - believe me!
Do you plan to completely wean from bfeeding, or just replace a feed with a bottle, but keep feeding around work hours? If the former, then I can't offer advice at all, but if the latter, I can say that we found it fairly straightforward, if a little disorientating for a few weeks.
I went back (5 days, 9-3) when DS was 7 months old. I kept on with all the other feeds, but he got a bottle mid-morning from the CM. Either expressed breast milk, or formula, depending on how much I'd managed to express the previous day. I won't be bothering with expressing for DC2, she can just have the formula once a day! We also did BLW, and the CM was happy to support that - she asked that we provide food for DS until he turned 1, and was happy to let him eat finger foods, when the other children she minded were having their lunch. He always had some cheese and a pot of yoghurt or fromage frais (which CM spoon fed him, which I was happy for her to do), to keep his calcium intake high during the day.
DS did ramp up his night feed demands, but not by much (I say this as he was always a poor sleeper, who would happily feed every hour or so during the night, so nothing would really feel like an increase!!), and I made sure he got a feed before work in the morning, and as soon as I picked him up in the evening.
He is still feeding once a day at 2.4 btw, so it is possible to keep bfing when you return to work, without it being a massive time commitment!
Good luck :)