I-ve heard: "All I wanna do is to play soccer" and "All I wanna do is play soccer". Both are correct? Thanks for your help.

Yeah, both are okay.

'To play soccer' is a noun clause. The infinitive form of a verb is often used in this role.

The clause 'play soccer' is simply the active verb.

Both are acceptable in your example.

I would save the word "clause" for a phrase with both a subject and a verb.

I wouldn't recommend writing "wanna" at all, or saying it unless you can do so very quickly in the off-space between stressed syllables, so as to deemphasize the words "want to", thereby stressing the following verb. This is very hard for non-native speakers to do, usually, at least at first.