White's thematic 9.Qe1 is useless because a/ black's has not castled yet and b/ white is wasting time recovering the pawn after 9...cxd4. Because of this continuation, 8.00 is often rejected as a feasible continuation. But can white not improve ? Let's have a closer look.
9.Qe1 cxd4 10.Ne4 ( concentrating on black's kingside instead of the timewasting 10.Nxd4 Qb6 11.Be3 and now black can start exchanging toards the endgame with 11...Ng4 ) and now there are various moves for a black advantage, such as 10...h6 or even 10...Qb6. So let's dismiss 9.Qe1 quickly.
9.Qe2 cxd4 10.Nxd4 ( 10.Ne4 is punished by 10...h6 or even 10...00 ) and now there are several black moves that give a small advantage to black ( eg 10...Qb6 or 10...Nc5 ). So it gets clear that 9.Qe2 wont bring anthing either - it is obviously better than 9.Qe1 but not enough for full equality.
So let's look ar 9.Kh1 - our last possible line before we burry 8.00 forever.
a/ 9...cxd4 10.Nxd4
a11/ 11...Bd7 12.Bxf6 Bxf6 13.Qh5 and black has only one move, eg 13...Rac8 14.Bxd7+
a12/ 11...Ncd7 and white has several moves ( Bxf6, Qe1 or Qf3 ) for equality
a13/ 11...Nfd7 12.Bxe7 and white wins
a2/ 10...h6 11.Nxe6!!! fxe6 12.Bg6+ Kf8 13.Qh5 with equality
a3/ 10...00 11.Qe1 transposing in the line b1 discussed below.
b/ 9...00 10.Qe1 (following the standard attacking lines)
b1/ 10...cxd4 11.Nxd4
b11/ 11...h6 12.Ne4!!!
b111/ 12...hxg5 13.Nxg5 equal
b112/ 12...Ng4 13.Bxe7 Qxe7 14.Qg3 equal
b113/ 12...Nd5 13.Bxe7 equal
b114/ 12...Ne5 13.Nxf6+ gxf6 14.Bxh6 equal
b115/ 12...Qb6 13.Nxf6+ Nxf6 14.Bxf6 Bxf6 15.Qe4 Rd8 16.Qh7+ small white advantage
b12/ 11...Nc5 12.Rd1 equal
b13/ 11...a6 12.Qh4 equal
b2/ 10...h6 11.Nxe6!!! transposing into line a2 above
b3/ 10...Re8 11.Qg3 equal
c/ 9...h6 10.Bh4
c1/ 10...00 11.Qe2 equal
c2/ 10...cxd4 11.Nxd4 equal
c3/ 10...Nd5 11.Nxd5 Bxh4 12.Nxh4 with white advantage
c4/ 10...Qc7 11.Nb5 equal
c5/ 10...Qb6 11.Qe2 equal
d/ 9...Nd5 10.Nxd5 with white advantage
e/ 9...a6 10.Qe1 equal
f/ 9...b6 10.Qe1 equal
So where is the black advantage after 8.00 c5 ? There is none - it seems to me that 9.Kh1 provides white an equal game. Agreed, white does not have the attacking prospects as in some other lines in the Euwe defense, but it seems white is certainly not lost. In addition, 8.00 allows black to go wrong by kingside castling.
Black's best line after 8.00 c5 9.Kh1 seems to be the quiet 9...h6 ( line c above ), with a Houdine assessment of 0.2 in black's favour.
So once again, don't believe everything the experts say ( that also goes for me... ), do your homework and keep on attacking that black king...