Yeah... the first batch of cider can be something that you don't expect.
At 1.009 it should still have a sugar concentration of around 23 grams per litre. This is about the equivalent of a teaspoon of sugar in a cup of coffee so there should still be a touch of sweetness.
As suggested above, time does wonders and I would typically leave my cider in a primary fermenter for about two weeks then transfer to secondary until it has reached the SG that I want for bottling or even longer (a few months). Even if fully fermented, adding sugar to taste plus a bit more for carbonation will give you an idea of how it should end up.
For a slightly sweet cider, I will typically bottle at around 1.010 to 1.012 then heat pasteurise when carbonation is at about 2 volumes (a SG drop of 0.004) for a modest fizz and a FG of around 1.006 to 1.008. Using a soda bottle as the "carbonation monitor" and doing a periodic squeeze test is an easy way to assess carbonation (I use a Grolsch type bottle fitted with a pressure gauge and look for about 30psi). If you end up with a SG of 1.006 or so, it should have a touch of sweetness.
Unfortunately IME, some champagne yeasts such as EC1118 are quite robust and tend to "blow off" some of the flavour compounds if they ferment too quickly , just leaving malic acid which is quite tart ("low and slow is the way to go"i.e. temp and fermentation) . To get from 1.042 to 1.009 in a few days suggests that this might be part of your problem. Do you have a Total Acidity test kit or at least pH test strips? if your TA is well above 0.6 or pH is below 3.5 you might find that acid is dominating the taste.
If you add any sugar, it will be consumed by residual yeast until you disable the yeast by pasteurisation. If you don't want to monitor carbonation, letting the SG drop to about 1.005 would be a good time to bottle as the remaining sugar will then only generate around 2.5 volumes of CO2 (i.e. about the same as bottled beer etc). One volume of CO2 will be generated from a two gravity point drop (i.e. drop in SG of 0.002)
For sweetening, using a non fermentable sweetener avoids generating more CO2 although some of these do have a strange aftertaste and can cause gastric issues. I have used Xylitol without any issues and its quantity and taste is quite similar to sugar, but beware it can be toxic to dogs.
Hope this helps.