iTunes account -- Yes, you can use the same iTunes account on multiple iOS devices. Currently, between my partner and me, we have two iPhones and 4 iPads on a single iTunes account.
Cellular account -- As previous poster said, if you want to use cellular service on both iPads at the same time, each iPad would need its own data plan. However, if you only need to use one iPad at a time, it is possible to swap SIMs. You didn't say which iPads you had, but if they are different models they might have different size SIMs, in which case you will need a SIM adapter. Also, swapping SIMs is a fiddly business, and I personally wouldn't want to be doing it every day.
You say one iPad is for work use only, so if you have wifi at work, then I don't see any need for a cellular plan for that iPad. If the work use requires a cellular connection, then your office should pay for the data plan.
Another idea is that some carriers (like Verizon, for instance) lets you use your iPad as a hotspot. So if you have both iPads with you, then one can act as a hotspot for the other, and they can share a data plan that way.