As a Carte Blanche holder you could, in principle, go through the Business Premier check-in and arrive 45-60 mins in advance even with a Standard ticket. However, it's not clear if this privilege extends to family members. I dare say you can probably do this if you ask first at the check-in because in reality there aren't that many CB holders out there but, like most things with Eurostar, one must expect the unexpected so one can't bank on it.
I would also respectfully suggest making sure you have some water and a snack for each person with you (liquids are fine through security) as, if your train is delayed or stuck somewhere (particularly if the power goes off), the hold up could be long and ES has only a minimal back-up provision. Three trains were held-up at Brussels Midi for up to four hours the Friday before last following a Thalys train hitting an animal near Halle and the barcar stocks soon ran out. Also, during the recent very hot weather, a Thalys got stuck and the power went off. I believe the pax ended up smashing the windows for ventilation.... the train is out of service for repairs. Having been in an incident like this about 15 years ago, let me assure you that it is wise to have some 'Plan B' capability with you. (And, thanks the cutbacks in compensation provision, you will only get 50% of the fare paid back in such a scenario....)