It is never too late to introduce a clicker but be sure you know what the clicker's purpose is and why it is sometimes a good choice (and sometimes not a great one).
The clicker is not really a reinforcer, it is a clear and umambiguous marker that a reinorcer is on it's way. You always follow it straight away with a reinfocer, such as food.
It's two main benefts are
a) it is a quick short noise so allows you to be precise about the behaviour you want to mark and then reward. i.e. if shaping a complex behaviour starting with something easier. So, if I wanted to train the dog to spin I might use a clicker to mark the turn of his head as spinning starts with turning. Then slowly increase my criteria until I have the full spin. The clicker allows me to be split-second quick about what behaviour I want.
b) it is the same noise everytime, thus doing away with any variation of voice and the impact that might have on the dog. e.g. frsutration creeping in and the dog reading that as a punishment.
From your description, it does not sound like a clicker is what you are needing. I wouldn't use a clicker for recall. I would use long lines and really high value treats and praise. If she loves a ball then this is one of the behaviours where you can use it to great effect. But in a limited way to prevent over excitement.
In fact, one of the main downsides to using a clicker is that it 'takes up' a hand. Recall training, with one hand maybe on a lead, one on a poo bag and one reaching for treats (already too many hands) might be an occasion where I would not recommend a clicker.
Ditto loose lead - to many things to do with too many hands, for me. I would be using treats to lure/reward here, I think.
I hear what you're saying about food not being a great motivator (in which case the clicker will suffer the same fate - because the clicker is only ever as otivating as the reinforcer you use with it). Not unusual for young dogs not to be food focussed - perservere.