First, you have to understand that the numbering system changed, so 79 Cedar Ave. became 1004 Cedar Ave. and 80 became 1006. Here is a transcript from the Russell divorce where Maria explains. It is from 1907, but the time period she speaks of is in the late 1800s through early 1900s.
There is other evidence of C.T. and his father, Joseph (and also Emma, Joseph's wife/Maria's sister) all living at those addresses in census records and other historic documents from that time period. It is definitely not CT Russell's boyhood home, but he and his father did own them and they both lived there at various times as married adults. In fact, I believe CT's father, Joseph, died in the 1006 side, but I can't put my fingers on the documentation at the moment.
Here is one screen grab from the 1879 Directory of Pittsburgh and Allegheny, where Joseph and Charles are listed as living in the same place on Cedar. (Obviously, the F is a typo). I can't any reference to a 79 Cedar Street, so I am wondering if they considered both sides the same address back then.
From the 1881 Directory (After both were married):
From the 1882 Directory:
There is still more you can find on your own with enough digging. The house was definitely not build in 1900. I am not sure when it was built (it would be interesting to find out), but I believe the date listed on the real estate listing is either a typo, or just completely wrong.
CT Russell lived at many, many other addresses from what I have found, but I believe this was the one he was living in with Maria with they first married and started the Watch Tower.