Are Credit Card Points, Airline Miles, and Store Credit representations of M2 money supply?
It seems unlikely that any authoritative source would consider credit card points, airline miles or store credit as apart of M2 money supply.

As you have probably read on investopedia:


  What is 'M2'
  M2 is a measure of the money supply that includes all elements of M1 as well as "near money." M1 includes cash and checking deposits, while near money refers to savings deposits, money market securities, mutual funds and other time deposits. These assets are less liquid than M1 and not as suitable as exchange mediums, but they can be quickly converted into cash or checking deposits.


According to this definition, credit card points are not counted to as apart of M2 money because they are not directly tied back to a cash exchange directly,(though there are some firms who will purchase them,) but are tied to specific services provided by the authorizing firms.

Since Credit card points are only usable for a specific services and are viewed  as  "in kind" transfers  rather than actual money.