According to page 17 of the chart below, your model (28907) uses bagger 24891.
Here's the chart: i.sears.com/s/d/pdf/mp-tc/spinpdf/spin_prod_1282253212
Here's your bagger: searspartsdirect.com/product/byggheq5cp-0071-917/id-24891
You can find all parts, diagrams, and your owners manual on Sears PartsDirect: searspartsdirect.com/model/tp54wws1wt-000247/craftsman-917289070-front-engine-lawn-tractor-parts
You can get 10% off on orders on www.SearsPartsDirect.com
when you use the coupon code TAKE10.