Hi,
The normal route of Aneto is over a 5 Km long glacier. They usually say that September to November is the worst season to climb the mountain because the crevasses open and the possible fallen snow could cover them. I think you wont need crampons but an ice axe would be recommendable and 2 poles could help you as well. However you wont be wrong if you bring a pair of crampons with you. A roped team would be a very good idea when crossing Glaciar de Aneto. Take care when passing Paso de Mahoma, a short but narrow comb before the summit cone.
BTW, Grizzlies will have a very good base this year, "La Bomba" Navarro is a great player