In principle. yes, but it strongly depends on the kind of the conference. Some prefer publishing consolidated research, some prefer brainstorming about non-discovered or not fully described or not yet explained research phenomena. The latter ones typically organize forum/discussuion sessions or dedicate workshops for given topics. Furthermore, there are conferences/symposia which are interested in methodological approaches rather than only in justified, validated and/or consolidated findings/propositions of scientific inquiries. In general the archiving nature of the overwhelming majority of conferences is weaker than that of peer reviewed international journals, while they are the first forums for letting early works/results out for public debate.
I think you have to have it carried out first so that the theory should and must be tested first. How can you say that it is a research when in fact it has not gathered data and evidence to its merit.
Surely it depends on the field and conference tradition. But generally, there are many conference publications that just present design research, or case study design, or both supplemented with some sort of pilot study or preliminary results. So the answer - yes.
If you’ve had your proposal accepted, and the conference coordinators are clear on the fact that your research is at the planning stage, and they feel it’s appropriate for the conference’s theme/approach, then with their encouragement you could go ahead.
That said, personally I’d prefer to have something -anything- solid to present, even if it’s only a small sample or snapshot of a work in progress. I feel this gives a conference presentation direction and authority, based on actual experience, rather than theory. I feel this helps confident, professional delivery very greatly. When you speak, you have a real basis for deductions and conclusions however tentative.
To be honest presenting at conference can be more nerve-wracking than you’d think. It can be exhilarating or you can sit afterwards and fret about your delivery/performance. It can be demoralising. It’s inevitable that you compare yourself with others. It was watching terrible presentations that made me think that I could actually communicate ideas and research in a reasonable way, but getting across the rigour and depth of research in twenty minutes, without rushing it or being dull, is a real challenge. I know I feel I’ve failed, despite positive comments. If this is your first conference presenting, perhaps waiting until you’ve had a chance to carry out at least part of your research might be your best plan for keeping it all manageable and positive.