You must include IELTS with your application, else you'd get your application returned. See below from the CIC website.
Language testing – Canadian Experience Class
To prove your language skills, you must take a language test given by an agency that is approved by CIC, and include the results with your application.
You must
Arrange for testing by an approved agency. You will have to pay the costs. Include the results of your test with your immigration application. If you do not, we will not process your application and we will send it back to you.
To add, there is a question on the form that asks whether you have attached/included the language test. Not possible to submit it later. Check whether the test is scheduled earlier in a neighboring city and whether you can transfer your centre and write there. Don't know if it's possible though.