If the 'community officer' was a was actually a PCSO, they can be designated the power to confiscate stuff, usually alcohol and tobacco from under age persons.
Powers Vary with forces.... Most have the above though...
I think the threat of confiscating the ball is something of an empty threat, however yes you would be able to get it back (though not the alcohol or fags if that was the case).
The ticket will actually be a stop account/stop search form, your son will not have been searched unless there was something else that you are not being told, police cannot indescribably search people.
The form issued will actually be a used to record a stop account, which the PC/PCSO was at the time you made your inquiry obliged to issue to anyone who is asked to account for their actions/presence - it came out of the Stephen Lawrence Enq. The minimum needed to be recorded is Name, DOB, and ethnicity. However other things are recorded as a matter of course - i.e. reason for encounter.
This form is placed on record, but is not a criminal record and will not bite him on the bum later. If your son starts to get vast numbers of these forms for consitantly being in the wrong place wrong time, when should be in school, in possesion of alc etc i would expect a knock at the door to discuss it, but it is not going to affect his chances of employment/college/uni etc.
Work with your local PCSOs, why dont want to move the kids on playing, kids playing isnt a crime, however the damage that CAN occur is however and therin lies the problem.
HTH