Hard to say without having a better appreciation of how the hands played out (starting stacks, number of players, betting action, etc). Detailed information on what your set was vs. the 9’s, for example would be helpful as well. Responses will differ if you flopped a set of deuces on a board that ran out 10 high.
When playing no limit, it’s obviously important to exploit every edge to its maximum potential.
As a general rule….I tend to bet my value hands a bit larger against those players I consider to be “sticky”.
Good Luck at the tables.