Yes you can freeze marshmallow cream.
Marshmallow cream will freeze just fine and when in the freezer the marshmallow cream will last for 3 months before it starts to lose it's quality.
So eat the frozen marshmallow cream within 3 months of freezing it for best results and taste.
Also be sure to try and get as much air out of the marshmallow cream container before freezing it and use the marshmallow cream up before 3 months.
Because the longer the marshmallow cream is frozen the less tasty it gets because it loses it's flavor overtime.