Hugs hun. I agree with Nicole that he's OT - I especially think he's OT for the second nap, but mainly because of the loooong A before the first one. Can nursery put him down earlier? What time does he get home - will he be at nursery for the second or at home? When you first do short am, it's not uncommon to have a couple of days of two short naps so I'd stick with it and see if the second nap lengthens out.
What about aiming for something like this:
WU 5.30
nap: 9.15-10.00 (capped)
nap: 1.30 - 3.00
bed: 7ish (earlier for a day or two if you think he's still tired and needs it to catch up)
This should gradually push the WU later, fingers crossed. If the second nap is short, do EBT as you have been doing, but stick with it for a few days.
What do you think?