hello! & congrats on still bf and on getting back to work.
DS is now 32mo, after a very rocky start to bf - hence I decided not to wean when I Went back to work (after you have worked so hard at something it seemed a shame to just let it go!!!).
Like you we never really had much of a routine and I also went back to work when he was 9mo and did a 3 day week until he was 1. Then i went up to a 4 day week. (I now do a full week) I was away from him from about 730/8 in the morning until 630 ish in the evening. He never drank milk whilst he was with either of the Childminders we had between 9months and 22mo.
Luckily I had read a US book from the local LLL library about returning to work, as well as the kellymom site. Both had mentioned reverse cycling so when DS did not take milk I was not taken by surprise. We had also been on a ski holiday the month before so had a trial run with DS in the creche and me skiing. It was then we realised he would not accept any type of milk in a bottle or a cup and would wait for me to bring the milk bar to him!!!
I was always a terrible pumper and it seemed a real hassle so although I took the double pump (in its back pack!) to the office for the first week I never used it. There seemed little point if I did not need to for comfort & if DS was not going to drink it!!!
I warn you that from about 4pm in the first week or 2 back my boobs would feel heavy. Woe betide any commuter who came too close to me on my way home!!!!!! However this calmed down pretty quickly.
When I arrived at the CM (& in the early days I arrived as close to 540/6 as I could manage) I would bf DS. He would fall upon them like a starved man - despite me knowing he had eaten well that day and drunk plenty of water :) I guess he had just missed me.
I really fretted about bf & my return to work. I should not have done. It was the least troublesome aspect of my return!!!
Over the last 2 years I have been on week long work trips and short trips too. I have never pumped. My supply has been fine. Our bodies are amazing things! DS now only nurses bedt & wake time, & not even every day now, so it is clear to me the weaning process is under way.
However in the early days I bf on demand on my days off and over night. Again there seemed no problem with supply at all.
I must say that the lack of sleep affected how I felt about work but I do not believe he was any worse than anyone else's 9mo so I just tried to sleep a bit more on my days off and tried to exercise outside too.
DS was not sleeping through the night at 9mo and shortly after my return to work this did get slightly worse, probably coincidentally judging by other friends going through similar things even if they had been back at work months or were SAHMs. Luckily we were part time co- sleeping so I did not miss out on any more sleep than before. At 12mo we moved him to his own room and one of us would part time co sleep inthe spare room bed with him, although it was usually me because he wanted Mummy Milk. At 14 mo we moved him out of the cot (he kept climbing out and we woudl find him on the floor!!!) into the spare room double bed and suddenly, perhaps coincidentally again, he started sleeping for longer periods. Gradually his sleep stretches lengthened and between 12 & 20 months he reduced his nursing sessions to wake up, bed time and only other times if something upset him!!
I am glad I continued bf on my return to work. It really helped me stay connected to him and when things got tough at work it would help remind me what was really important.
Best of luck with your return and enjoy the last week of your mat leave.