A couple things: solid state batteries weigh much less. Solid state batteries are 30-50% lighter per kWh. The initial ones will probably be closer to 30% lighter. A 100 kWh battery weighs about 1400 lbs (635 kg). Shaving off 400 lbs is pretty significant and results in much better range for the same battery capacity. The battery pack is likely closer to 150 kWh.

Second thing would be the charge rate. Yes, a supercharger can 250 kW output (not kWh BTW) but a few factors means that they often do not. First thing would be heat. If the charging cable or the battery gets too hot, the the rate slows down. The next thing would be the fact that current batteries have to start at a slow rate and end at a slow rate. Solid state batteries do not have those issue nearly as much and can more consistently hit that 250 kW output for a longer period of time.

This thing, they are likely using 350+ kW chargers. Higher than 350 kW is pretty rare but the odd 400 kW and 450 kW charger does exist.

And doing some more digging, I found that it is from 8% to 80% in 9 minutes. And even then, it does not say it is the same 150 kWh battery that is being charged that fast. This could be marketing crap where it is giving numbers for a ~85 kWh battery to compare it to EVs today. An Ioniq 5 takes about twice as long to go from 10-80% at 350 kW.