Bring wine, a pinch of salt, bay leaf, celery, and fennel to a boil in a medium saucepan. Reduce to a simmer; cook until vegetables are just tender, about 8 minutes. Transfer vegetables to a medium bowl; discard bay leaf. Set aside. Add scallops to pan; simmer until just cooked through, about 3 minutes. Transfer scallops to bowl of vegetables; refrigerate until cold, about 30 minutes. Reserve 1/4 cup poaching liquid in a small bowl. Refrigerate until cold, about 20 minutes.
Stir lemon juice into poaching liquid. Add oil in a slow, steady stream, whisking until emulsified. Slice scallops in half horizontally; toss with dressing and vegetables. Season with salt and pepper. Toss herbs, celery leaves, and fennel fronds in a small bowl, then divide among 4 serving plates. Top each with scallops and vegetables, dividing evenly. Drizzle with oil and dressing from bowl. Garnish each salad with a lemon wedge.