The user votes average on film X is 9.4, so it should appear in your top 250 films listing, yet it doesn't. Why?
As indicated at the IMDb Top 250 Films page,
only votes from regular IMDb voters are
considered when creating the top 250 out of the full voting database. This
explains any difference between the vote averages reported in the top 250
and those on the individual movie pages. This also explains why movies you
might think from their averages ought to appear on the list yet do not
actually appear there.
To maintain the effectiveness of the top 250 list, we deliberately do not
disclose the criteria used for a person to be counted as a regular voter.
Please be aware that the Top 250 list (and the Bottom 100 chart) only include theatrical features: shorts, TV movies, miniseries and documentaries are not included in those charts.
Top-rated documentaries are listed in a separate chart.