How to Install:
1) Download File "Minecraft RCON Mac"
2) Extract/Unarchive the "zip" file
3) Open the "Minecraft RCON Mac" app
How to use:
1) Enter address : port (ex. 123.456.7.890:1234)
2) Enter RCON password for the server (not on PC server config by default)
3) Enter command to execute
Notes:
1) Mac ONLY
Links from here
2) No, I didn't use the program from that site I took the Windows version from a guy named Creator_James (Minecraft IGN) aka TheCreatorJames (Youtube) and converted it to Mac (I will not say what program/site I used)
His program is here
3) It will take a few seconds to load

Minecraft RCON Mac 1.0
Mc RCON for mac