YES! And it's brilliant!
I've had children in my Codeclubs that cover a wide range of additional needs since staring them over 3 years ago. The first child ,S, was someone that I knew about anyway as I knew his parents, and he became my 'right-hand man' for his final year in primary
The first time I realised that I had a child with different needs was a bit scary for me, as I am not a teacher and had no experience in dealing with kids. G was very fidgety for the whole of his first session, constantly getting out of his seat and wandering around, not focusing on the task. When his mum came to pick him up, she asked how he had got on and said she was worried because of his ADHD, at which point his behaviour made more sense. A couple of days later, I managed to grab a chat with the school's SENCo (I must point out that I am also a Governor at the school and a PTA member, so am well known within the school, which gives me a bit more access to school resources than a regular volunteer) and asked about G. She told me what the issues were, which also included dyslexia, and we spoke about how that was managed in class and how I could manage it in Codeclub to help G get as much as he could out of it. For the next week, I printed the project resources out for G, on a cream-coloured paper, and made a point of making contact with him every 5 or 10 minutes. He stayed focused and concentrated all session and didn't leave his seat once
The SENCo is now my first port of call at the start of a new term. She goes through the list of kids with me, highlighting any that have additional needs and giving me ways of managing those in Codeclub.
I have learned a lot about SEN requirements, especially (and this is so important with autism) that there are endless variations in how any of these conditions presents in any given child. The child I mentioned right at the start, S, was very capable but had problems with socialising and relating to others, as well as being averse to a lot of sensory input. But he was very good at self-managing and would often wear ear-defenders to help him concentrate. Some of my current groups have anxiety issues and like to listen to music, so they do that (through headphones, of course!) either via their phone or from a (carefully monitored) Youtube channel.
I currently have one young man, who is in Yr4, who is awaiting a diagnosis for autism. E is really bright but has a very limited attention span. I use a similar tactic to the one I used with G, in that I try to make contact with him at least every 10 minutes and, instead of letting him work through the project on his own, I talk through each section with him and set him the task of finishing one part before asking for me. I find this helps him to stay on-task, and he delights in ticking the boxes on the Codeclub resources when he has finished a particular section. He'll then quite often come and take my hand and lead me back to his seat so that he can show me what he has done
So, for me at least, I would say that the best thing has been having access to the SENCo and the other teachers so that I can talk through any issues and use their knowledge and experience to help me ensure that the kids get as much out of Codeclub as possible. I also feed back any issues that I see and, indeed, anything that I think needs to be celebrated in a wider setting. I have found that some kids that may not be particularly gifted in regular classes often find something that they really excel at and enjoy in Codeclub, so I always make sure to feed that info back to the teacher.
As I said at the start, I was scared when I realised I had a child with extra needs, because I didn't know if *I* could deal with it. Now, I love having these kids in my clubs as it brings a different dynamic as well as new challenges (not just for me, but also for some of my 'old-timers' that I use as mentors occasionally) and in all honesty, these are the types of kids that stand to gain so much from participating in something like Codeclub.