Preheat oven to 375°. In a 9-in. square baking pan, toss sugar, vanilla bean and seeds, star anise, and orange zest to combine. Halve rhubarb lengthwise, and if stalks are large, split again lengthwise. Cut pieces about 2 in. long on a diagonal and combine with sugar mixture. Stir in wine along with pepper to taste.
Bake until rhubarb is tender when pierced but still holds its shape, 15 to 20 minutes. With a slotted spoon, transfer rhubarb to a shallow bowl; discard star anise.
Pour rhubarb juices into a small saucepan. Bring to a simmer over medium heat, then simmer until reduced to 1/2 cup, 6 to 9 minutes. Pour over rhubarb. Let cool, occasionally spooning syrup over fruit.
Set meringues in bowls. Spoon fruit and syrup on top, discarding vanilla bean. Add a spoonful of crème fraîche to each and sprinkle with pistachios.
Make ahead: Through step 3, chilled, up to 1 day.