Yes it’s all swimmers under 18 who need accompanying poolside. There are ratios for this and a lot of clubs won’t accept individual entries even if you can make the required ratio standard.
But I would speak to your club. Many don’t “allow” or want swimmers just going off and doing meets everywhere. The season is planned into 3 phases (run alongside school terms although age is end of year!) and each phase will have different goals and target meets set around the training plan. This will also be squad dependent and aimed around what meets squads are aiming for and qualifying meets for counties etc.
some clubs will encourage swimmers to go to higher meets (see above about needing L2 as too fast for level 3) but the coaches will work the programme to peak at these meets for the swimmer.
an example is our juniors, regional and national squads will all swim counties but it’s a target meet for the juniors so they taper -‘our regional and national swimmers train through it. Regionals the regional squad taper and national swimmers train through as they have usually just come off British champs and are aiming for summer meets.
My ds will follow a slightly different programme because he’s a para swimmer and so has different target meets throughout the year alongside British champs with his squad.
The coaches have to work a really tight schedule of planning to ensure they don’t burn out swimmers but equally they don’t taper them too much in a year either!
At 9yo I would just go along with the squad to meets and have fun. But I would train to do a role (TM or official) because they are crying out for them and also because it passes the time and saves a fortune in spectator fees after a few years!
If they start qualifying for regionals when they are old enough you can start needing hotel stays and if they get to national level it can be whole weeks away at a time and £15- £20 a race.
If they make programmes there’s travel at weekends.
But you won’t know where your swimmers journey is going at such a young age and so loving the sport and getting good technique is the aim.