Prohibited Items? Probably Not.
Ceramic dishes shouldn't qualify as forbidden items, according to Ryanair's Terms and Conditions, which state:
Q: What items are prohibited onboard a Ryanair flight?
You cannot bring the following items onboard a Ryanair flight or in airport security restricted areas in the airport:
- Guns, Firearms or similar weapons
- Pointed/edged Weapons & Sharp Objects
- Blunt Instruments: any blunt instrument capable of causing injury, this includes some sporting equipment such as tennis rackets and baseball bats
- Explosives and flammable substances: any explosive or highly combustible substance which poses a risk to the health of passengers and crew or the security/safety of aircraft or property.
- Chemical and Toxic Substances: any chemical or toxic substances which pose a risk to the health of passengers and crew or the security/ safety of aircraft or property
The carriage of liquids, aerosols and gels into the security restricted area of an airport and onboard aircraft is controlled in accordance with current EU Security Requirements.
More details on items prohibited onboard Ryanair flights can be found on the Terms and Conditions webpage here.
How about Carry-On Size and Weight?
Your real worry should be the size and weight of your carry-on luggage. According to Ryanair Terms and Conditions:
Q: What cabin baggage can I carry?
You can carry one cabin bag weighing up to 10 kg with maximum dimensions of 55cm x 40cm x 20cm, plus 1 small bag up to 35 x 20 x 20 onboard the aircraft.
Due to cabin space limitations only 90 large cabin bags (55 x 40 x 20 cms) can be carried in the cabin, any bags remaining will be carried free of charge in the aircraft hold.
Passengers who have purchased Priority Boarding will not be asked to place their cabin bag in the aircraft hold, unless necessary due to operational reasons.
All the information you need is in the quoted text above. You have an allowance of 55cm x 40cm x 20cm in which you can fit a maximum of 10kg. In terms of size you should be fine, provided you pack the dishes as compactly as possible. The real question is the weight. You mention the whole set weighing 9.5kg which leaves you 0.5kg for padding and bubble-wrap. That might be on the short side, depending on how fragile these dishes really are.
Finally, you'll want to minimise the chances of having your hand luggage placed in the cargo hold upon boarding. Ideally you'd want to pay extra for Priority Boarding, as suggested in the T&C quoted above, and make sure you are one of the first to board the aircraft. The assumption is that, if only 90 pieces of large hand-luggage are allowed on board, you'll want to avoid being the 91st in line for boarding the plane.