The WICC also has hotel accommodations and rooms have been reserved for congress attendees. Indicative prices per room per day for overnight stay plus breakfast are €85 for a single room and €120 for a twin room, incl. VAT, excl. tourist tax (about €3 per person per day).
You are expected to book your own rooms at the WICC (details and booking codes will be provided here in due course), but you are of course free to choose other accommodation of your choice in or near Wageningen.