You can create a button on any PDF document (a blank document, for example) and place the following script as a "Run a JavaScript" Action in its Mouse-Up event. This document can be used even with Adobe Reader.
console.show();

You can also create a tool button using the following script as a folder level JavaScript. The tool button will appear under Add-on Tools:
// add a tool button
app.addToolButton({
cName: "showConsole",
cExec: "console.show();",
cTooltext: "Show JavaScript Debugger",
cEnable: true,
nPos: 0,
cLabel: "JavaScript Debugger"
});
