Dear Florent,

There is a sentence in the Mahaaparinibbaansutta that has a "vandite"
in combination with an instrumental like the one you cited from Ja I
87:

Vandite ca panaayasmataa mahaakassapena tehi ca pa~ncahi
bhikkhusatehi sayameva bhagavato citako pajjali. --- D II 164

And on account of what was venerated by the Venerable Mahaa Kassapa
and the five hundred bhikkhus, the funeral pile of the Blessed One,
just by itself, burst into flames. (my translation).

"vandite" in the locative singular might be from the neuter
noun "vandita.m" like "bhaasita.m" in "tena bhaasita.m" --- what was
spoken by him (see Kacc-v 556).

The locative sense might be as "cause" (on account of) like
in "ku~njaro dantesu ha~n~nate" --- the elephant was killed on
account of its tusks (see Kacc-v 310)

So, based on the above, "ra~n~naa pana vandite . . ." --- could be
translated as "And on account of what was venerated by the king . . ."

I also thought of "veneration" (action noun) instead of "what was
venerated" (object noun) but ruled it out because it seems that we
would need a genitive "ra~n~no" to go with "vandite" according to the
examples given at Kacc-v 556, e.g., tassa hasita.m --- his laughter.

Best wishes,
Jim