Hm, I have the cleandb extension working locally against 1.8.2 and 1.9. For example, you can run
from neo4django.db import connection
from pdb import set_trace; set_trace()
connection.cleandb()
and trace the cleandb
Python call, and it gets a 200 and accompanying response body,
{\n "node-indexes" : [ ],\n "nodes" : 4,\n "relationship-indexes" : [ ],\n "relationships" : 0,\n "maxNodesToDelete" : 1000\n}
I'm not sure what the difference between curl and the Python call might be- any chance you could try the above in a module, run it, and see what happens?
EDIT:
The cleandb extension is unmanaged, so you can't (IIRC?) set the URL to '/db/cleandb', it needs to be on its own root- I use '/cleandb'. LMK if that helps!
EDIT:
Aw, disregard that, '/db/' urls seem to work fine. Maybe you could use the 'install_local_neo4j.bash' script (https://github.com/scholrly/neo4django/blob/master/install_local_neo4j.bash) to install a copy of Neo4j and set it up the same way, if that works for you? And if so, maybe we can see how the setups differ...