I bought something from Home Depot on December 13. It took EXACTLY 90 days for my points to post (March 14). You are not supposed to contact them until 90 days is up. Everything I buy via Walmart/HHPortal usually posts within 3-4 days. I am sitting on a TurboTax purchase to see how long it takes it to go through - currently about a month.
Personally I prefer the Delta SkyMiles shopping portal - it goes through within a day or two and is very reliable. I only use the Hilton one when a) vendor not available on Delta's portal, or b) I know I need Hilton points but I have a looong time to earn them. It's not a great portal site.