yes, HL2 for Xbox was clearanced at $8.96 along with a ton of other games, a couple months ago. yes, it's possible that some stores have been receiving more copies of clearance games from CC's warehouses, or some of the games have just continued to sit on the shelf because shoppers at certain CCs were unaware or uninterested in those particular games being clearanced (for example a great many of CC's stores did not change the price tags on all of the clearance items, although the games WILL ring up for $8.96 no matter what the price tags say).
my guess is that there might also be another reason some $8.96 clearance games ended up back on the shelves: ebay sellers (OMG FATWALLETEERS) ran out and bought a lot of these games with the intention of selling them on ebay, then had no luck selling 'em, so they returned 'em to CC for refunds quite a while after the initial buzz (re: everybody/CAGs looking for $8.96 bargains) died down. so... now that people are no longer really looking for these clearance games, the chances of finding some of them at CC are starting to get good(-ish) again.