So the 996tt has a vent tube for the battery as most of you know. My new car battery that I just got 2 vent holes that are opposed to each other on different sides. Obviously, I can't use the vent tube cause there are 2 small holes, but is this okay?

The luggage compartment is sealed, but the compartment up top has access to air.

 

If the batteries cells are in one long tray rather than two separate just plug one side and attach the hose to the other.
If two separate you could make a T and attach both.
I spoke to the dealership about this as the battery compartment is right beside the air intake for the cabin of the car.
He said it doesn't matter hooked up or not, 90% of the time they get missed or fall out anyway. I guess it must not vent a lot as it charges.
I know mine was not hooked up cause when I replaced the battery for the first time I found the hose under the old battery. I didn't notice any smell or anything during that time. But I hooked it up anyway.