I would generally check the specs of the equipment first, but the U-Line shelves of comparable size have a capacity of about 200-300 lbs per shelf. They are surprisingly sturdy.
In the case of that video, those tanks are 20 breeders, so roughly 200lbs each. That would be in line with that capacity. So, yes- They can hold the weight. Again, if you are planning on doing something like in the video, be sure to check the specs of the equipment you purchase.
Happy reefing!