hey, i usualy give them 10 min acclimation, sometime i just drop them in, I would not suggest putting inverts in 1.009.
you should continue to keep an eye on him, if he starts to smell its time to throw him away. just dont stick your nose right up in there or you will get a special treat
sometimes it takes a snail some time to get used to the tank.
when in doubt, see if he will stick to the glass, then you can watch from there. you may be able to observe its radula if it is eating.
dont give up till he smells
goodluck!
-oozy-