Holiday Inn Express, Aurora Avenue, Downtown Seattle. Room rate includes breakfast, hotel is modern and convenient for cruise terminal. Major attractions of Seattle all close by. Reception Staff have all local transport information.
Go to Expedia.co.uk, search for hotels in Seattle, descriptions of those hotels will tell you if near the port - also "Google" location of port to give you an idea of likely hotels nearby from the Expedia list. When in that hotel, make enquires for the day you return at the end of the cruise for storage of luggage. Most US hotels have a facility for storage of luggage for guests who have checked out but are not returning to airport until later in the day. We always find US hotel staff very helpful about things like that. Good luck.