Product review (4 stars): It just tastes better without the chlorine
1.  The information on Amazon for this Tier 1 RWF1021 replacement filter did not indicate the contaminants it is rated for reducing.  The carton for the original Kenmore 9915 filter says it reduces chlorine, particulate Class I, lead, mercury, benzene, p-Dichlorobenzene, asbestos and cysts.  According to the information printed on the Tier 1 filter, it says "independently tested against ANSI/NSF 42 Standards, for reduction of chlorine taste and odor."  According to the NSF website, ANSI/NSF 42 establishes minumum requirements for "reduction of aesthetic or non-health-related contaminants (chlorine, taste, odor and particulates) that may be present in public or private drinking water."  That evidently means the Tier 1 only filters chlorine and particulates.  Therefore it is not an exact replacement for the Kenmore 9915.  However, it is all I need for my purposes, because my tap water is perfectly healthy.  It just tastes better without the chlorine.

2.  The rectangular piece on the end of the filter that fits into a slot on the cap in my refrigerator is a tiny bit narrower than the original 9915.  This means it fits more loosely into the slot.  However, it still works well enough to be usable in my refrigerator.

All things considered - including the much lower than original 9915 price - I will probably order this filter again.