Looks like the front hole (hole nearest the pool) is the maindrain/equalizer port and it is plugged (2 skimmers/separate maindrain plumbing?). The back hole should be open, yes. Since I don't know what the object is, it would be hard to say how to remove it. Is it somewhat soft, like a plastic ball? poke a hole with a piece of wire, like a coat hanger. Bend a hook into the end, reinsert into the ball and try to pull it out.