No, the IELTS it not valid for a year after you have applied, it's valid for a year before you apply. That is, if you take IELTS today and you want to use it for your application, you need to apply within a year. If the IELTS is already a year old and you didn't apply yet, you have to take a new one. You can see that and more in the guide for skilled worker applications:
http://www.cic.gc.ca/english/information/applications/guides/EG72.asp said:
However, it is recommended that all applicants using this category complete their language test(s) or their written submission before submitting their application to the CIO in Sydney so that they know in advance how many language points they will attain on the selection grid.
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Your test results must not be more than one year old at the time that you submit your application.
If you really want to apply before taking IELTS, just guesstimate your points. If your application is accepted by Sydney and forwarded to the visa office, they will ask for your other documents, including IELTS. It is not important that you get exactly the points you estimated as long as you have at least 67 total. Just be advised that some people here have said that it takes up to 8 weeks in some places to get an appointment to take the IELTS so you should check into how long that takes in your area.