Title. And for archival purposes: this question is about/was asked when the current build was the Steam Early Access release build (Dec 18 2021).
For some reason, a quick search didn't yeld any results before, but it did now (I probably did something wrong before). Currently:
AI officers can be told to use the shield by: command menu > 'Deploy' > 'Deploy shield'. Do note however that the AI will switch from the shield when told to do a command that its unable to do with the shield (like opening or breaching a door, throwing nades, etc.), and will need to be manually told to equip the shield again.
AI officers currently can't use the battering ram. It is however expected that they will be able to use it in a future update. As it currently stands, adding it to their loadout is basically wasting the slot.