Well, it's technically possible that you may have establishments (rather than settlements, that are far more rare) along Volga (actually you most probably had reckon from Varangians historically), but I don't think it would be enough to really have an importance.
After all the Volga way was completly
taken over by Arabo-Islamic traders, as it pointed directly toward their territories rather than Constantinople (hence the islamisation of Bulgars).
Now, if for some reasons, Volga Bulgars were to collapse, you *may* have some Rus' influence earlier in the Upper Volga, eventually opening the region to a small (essentially traders, and non-permanant while possibly continuous) varangian presence.
But the economical decline of Abassids, the greater importance of Dniepr way, and the problem of scretching a presence that was already quite fine are huge problems to make it worthwhile.