Currently using 0.8.8-r1 on amd64, no problems ever experienced.
There are occasional system freeze and crashes, kdetv is not deemed stable yet.
I disagree. What crashes are you talking about exactly? I use it regularly and it works just fine. I don't see any amd64-specific reports of instability on this bugzilla. Firefox or SuperKaramba crash more often on my machine. If it's stable enough for x86, it seems to be as stable for amd64. If you have specific stability issues I have not seen, please specify, else I will reopen the bug.
0.8.8-r0 has an half-broken ebuild, I'm not actually sure _why_ it was marked x86 stable, but it shouldn't either. And on my system it regularly freezes the box every 2 hours. It's not stable enough for stable at the moment.
What is broken about 0.8.8? I do not see anything special (but it's long since I wrote an ebuild last). I see neither many complaints about kdetv in the forums, much less amd64-specific. From 2006, I found only this complaint about a compile-time error due to ATI binary drivers-is that what you are using? http://forums.gentoo.org/viewtopic-t-441762.html
I'm not using ATI, the problem is at runtime, I know what I'm doing, this is not going stable, don't waste others' time reopening this.
I was expecting a reply more like "It gives this message X when it crashes", or "It is incompatible with card/system layout Y" or "The ebuild is broken because it does Z instead of T" or "We had a discussion about this, see link K". That way things could actually get fixed.