8 months, what would think to do, what rules I think apply ...
Build up a freezer stock by expressing one ounce for a few days, then 2 ounces per day, then 3, then 4 ounces per day.
Once you have sterilised the pump, you can keep using it for the next 24 hours without resterilsing, as long as it's back in the fridge/cool bag between uses. Same goes for adding freshly pumped milk to previously pumped milk. As long as you keep it cool inbetween, and use it within 24 hours, no real risks. But I would freeze any unused milk at the end of that 24 hours.
In theory, you don't really need to sterilise at all if the pump is well washed inbetween uses, but I preferred to play it safe & almost always sterilised.
For work I either had a cool bag (so, put bag & pump & cool bag in fridge the night before, add ice pack next morning, & try to then keep them zipped up all day at work) or found a fridge at work that I could put the entire cool bag into during the day. The small portable soft cool bags are small enough for that.
Your employer is obliged to provide you with both time & place (somewhere private and clean -- not the toilet!) to express... but personally I didn't want to discuss it with my employer so chose to express in the disabled loos, after all.
AT 8 months my babies only took 2x 4 oz bottles (plus solids) a day while I was at work a full day. HTH.