Time in your homeworld stands still when sims are at Uni or traveling in any other world. If any of the kids are babies or toddlers, then you do need a babysitter or another household member teen or older to stay with them just for the brief part where the parents get into a vehicle and leave the world. It's not a matter of social workers, you can't leave very young kids like that alone on the home lot anyway. Same for the return home, the same babysitter or other household member will still be there as time will not have moved in your sims' absence.
The other way is, with the NRaas Traveler mod in play and set to allow for it, take the kids with them to Uni and stay in a house off campus. But someone has to stay with the kids during any periods when both parents will be in classes at the same time. I've never done Uni this way so I'm just assuming it will work as my sims have traveled with babies and toddlers to custom vacation worlds with Traveler.
