There’s an element of sweetness running through this dish – the pumpkin, of course, but also carrots and gently fried onion plus, to an extent, the cream too. However there are balancing, more savoury, vegetal flavours such as the stock and the celery. It all makes for a super soup, but a difficult wine match!
White wine devotees may find solace in an off dry white wine, but not with too much forward fruit – a fairly bland white therefore, perhaps from the Airèn grape variety with a touch of residual sugar remaining.
However I think the best partner, though not perfect, would be a young, light, fruity red. Joven (young) Cariñena wines always have good fruit content and often savoury, herby note too. Or perhaps better still would be a young wine from Bierzo, whose unique indigenous grape variety, Mencía also carries an earthy, mineral characteristic which would suit this dish well.