Tarminiana and mollissima are thought to be different species.
Read more about it for example here Passiflora tarminiana | Banana Poka | Passion flower
Tarminiana / mollissima are from the tacsonia group of passiflora.
If grown a few out of that group. Most tend to not tolerate frost. or only the tiniest amount. And are also sensitive to heat. (days above 30c they get sad)
They also tend to be more sensitive to roots drying out. Where other passiflora can usualy handle you forgetting to water them. Tacsonia’s just die.
However you picked one of the stongest out of the tacsonia group. And your in 9b so you should not have that many frostst
Mulching them helps for multiple reasons.
Although i have eaten passionfruits if grown myself. None of them id consider tasty. Im experimenting with some frost hardyer (but not truely frost hardy) species and hybrids to get tasty edible fruit.
If written about it here