Is it possible to access the right click/context menu of the currently selected item (not the item under the mouse) by way of using a keyboard shortcut?
If not, is there any way to achieve this, either by Applescript or utility?
There is no way in general on the Mac to determine the screen coordinates of the current insertion point. So there is no way to automate a click at the current insertion point.
In some apps, there might be a way to get the coordinates via AppleScript, or it might be possible to get them using some sort of private API or other system hackery, but there is no general solution to this problem that is supported by Apple APIs.
It is, apparently, quite a common UI gesture on Windows, but it is not something you can do on the Mac.
One could probably write an Applescript that moved the mouse over the selected item and do a right-click. Other than that, no, I don't believe there is a way.