No. While old batteries are a problem, the old PS2 boards that used 8.4 volt batteries contain components that are failing.
As to the Tenergy batteries, I can't tell if they are 8.4 volt or 7.2 volt. Rechargeable batteries, despite being called "9 volt" are not. They are either 8.4 or 7.2. In addition, several of your engines may use 2 rechargeable pencells, which yielf 2.4 volts. So until you open each loco up, and are sure what type they use, you won't know how many to get.
On the chance that some of your locos may have failed boards, I would only buy one or two sets of each type, and try each engine. Someone will probably recommend you buy what are called BCRs or supercapacitors to replace batteries. But they are expensive and it is better to use a cheaper battery to test engines.
