I figured out that shell runs bash (hence the error - "bash: ./geekbench ... permission denied.").
user chronos is the same as the build I have, methinks it is standard.
Last question is, where are the geekbench binaries (so we know which fs to remount)?
(go into the geekbench directory and type "pwd")
to elaborate, if they are in /home/chronos (NOT /home/chronos/user) type:
sudo mount -o remount,exec /home
or
if they are in /home/chronos/user, type:
sudo mount -o remount,exec /home/chronos/user
And if you are wondering, it is ok to remount by specifying "mountpoint" as opposed to "device", even if they are not in the fstab (which they are not).
after that, them binaries should run!