Cleon
Legend
Spell Penetration is probably ok, since the big guy might take on more special problems (like a phoenix). But, actually, before we get to the feats, let's look at the spell list, as that might suggest some feats.
That's a good idea. Although we may want to decide how many Improved Spell Capacity epic feats it gets to determine how many 10th+ level spells it has, it'd make as much sense doing that retro-actively as those spells will most likely have Metamagic feats applied to them.
Anyhow, the Domain spells should be the easiest to pick so shall we do them first. 8th - sunburst, 7th - regeneration, 6th - heal seem the most apt to me but I'm not sure whether to go for mass heal or prismatic sphere for the 9th.
Of the regular spell picks, I like the following:
9th: miracle, true resurrection
8th: dimensional lock, holy aura or shield of law, greater planar ally
7th: greater restoration, holy work or dictum, repulsion, symbol of stunning
6th: greater dispel magic, undeath to death, word of recall
What do you think?