Can I have a partial opinion in an opinion essay?
You shouldn't use a partial opinion in an opinion essay. Chris has done many years worth of research to find out the most effective way to deal with particular question types, including opinion essays. We have found that you are much more likely to get the scores you need if you follow Chris' advice and either have two ideas saying why you agree OR two ideas saying why you disagree. This will leave you with no doubt and absolute clarity in the exam, which will lead to higher band scores.
You can use the planning templates to help you prepare for them - Where are the Task 2 Planning Templates?