He appears from the photo to be a toy poodle, not a mini. He's 4.4 kg (or 9.7 lbs), which sounds about right for an oversized toy depending on it's height. Have you actually seen his parents, and if so, were they considerably larger? Or did you get him from a commercial seller like a pet shop or one of those farm-type situations where they brought him out to show you but you never got to see him with his mother? One problem with pet shops is they go by what his registration papers say (if any), which may not be accurate. Another problem is one parent could have been a mini (probably the mother) while the other was a toy.
You mentioned plans to breed him once this summer. Since he doesn't look like a minipoo, here are some thoughts about other genetic issues with this.
If either or both of his parents or some of his grandparents were miniature(s), and you breed him to a toy female, the pregnancy would likely be extremely difficult for her and might even kill her from carrying and/or trying to deliver one or more oversized pups. If you plan to breed him to a miniature, this wouldn't likely be a problem, however, the pups run the risk of having disproportionate bodies, i.e. their heads are too big for their body, or their hind legs are shorter than their front legs, or their back is too long or slopes in an odd way.
Other than his size heritage (toy vs mini), unless you've verified by sight that
both of his parents are normal sized minis, there may be other things you don't know about his genetic heritage. The most important of these is
what's in his DNA? In other words, is he carrier of a genetic condition? One cannot tell by looking at the dog. This is easy and not expensive to find out.
The Vet DNA Center offers a variety of tests. The best one that covers four of the five most common genetic conditions and is called the
Poodle Disease Panel and costs $98 US dollars. These will rule whether he is a carrier or will eventually develop blindness and two other common poodle problems. Ideally the female you have in mind should also be tested; if both dogs are carriers of the same condition (like PRA-PRCD), some of those puppies will become blind and all will be carriers. Ending up with a blind or disabled dog is traumatic for the owners and miserable for the dogs, so testing is the way to go to not end up with that situation. There are other labs that do testing but I gave you the least expensive that I know of in the USA; google "animal genetic testing labs" for your country.