Hard to answer definitely without a reproducible example since you didn't provide test data, but I think you'll get the desired result by using the aesthetic color for the geom_point:
...
ggplot(aes(x=Utopianism, y=scores, fill=wellbeing_subscale,show.legend=FALSE)) +
geom_point(aes(color = wellbeing_subscale, show.legend=FALSE) +
...
The point is that fill applies to surfaces (e.g. the smooth of the fitted line), but color applies to the dots and lines.
Also that means if you gave color in the ggplot() command, it would apply to both the points and the fitted line (which is currently blue).
ggplot(aes(x=Utopianism, y=scores, fill=wellbeing_subscale, color = wellbeing_subscale, show.legend=FALSE)) +