Can this product be glued down then put carpet square on top for insulation and padding? I want to use the carpet squares in a home gym located in the basement.

You can use AcoustiCORK RC1000 Underlayment under carpet tiles. The one thing when using and underlayment under carpet tile, it can't be too plush. It has to be pretty solid to keep the tiles from separating due to the pad depressing. You can glue this underlay to the subfloor and it will provide ample comfort underfoot and is a great insulator.